Additional Warnings in docs build on travis after merge of decxx

The following warnings in the Travis build of the docs are new. I believe that they are new after the merge of #3646 (They are there in the build log of that merge build and used to not be there but I might have overlooked another source of these issues) 

```
/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sankey.py:docstring of matplotlib.sankey.Sankey:86: WARNING: Exception occurred in plotting sankey_demo_basics
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/api/sankey_demo_basics.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 70, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sankey.py", line 741, in add
    tips = rotate(tips)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1671, in transform_point
    return affine_transform([point], mtx)[0]
ValueError: object too deep for desired array
/home/travis/build/matplotlib/matplotlib/doc/examples/api/joinstyle.rst:8: WARNING: Exception occurred in plotting joinstyle
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/api/joinstyle.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 624, in render_figures
    figman.canvas.figure.savefig(img.filename(format), dpi=dpi)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1470, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backend_bases.py", line 2194, in print_figure
    **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_agg.py", line 525, in print_png
    FigureCanvasAgg.draw(self)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_agg.py", line 472, in draw
    self.figure.draw(self.renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1079, in draw
    func(*args)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/axes/_base.py", line 2092, in draw
    a.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/lines.py", line 712, in draw
    drawFunc(renderer, gc, tpath, affine.frozen())
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/lines.py", line 1067, in _draw_lines
    self._lineFunc(renderer, gc, path, trans)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/lines.py", line 1107, in _draw_solid
    renderer.draw_path(gc, path, trans)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_agg.py", line 167, in draw_path
    self._renderer.draw_path(gc, path, transform, rgbFace)
TypeError: bad argument type for built-in operation
/home/travis/build/matplotlib/matplotlib/doc/examples/api/sankey_demo_basics.rst:8: WARNING: Exception occurred in plotting sankey_demo_basics
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/api/sankey_demo_basics.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 70, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sankey.py", line 741, in add
    tips = rotate(tips)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1671, in transform_point
    return affine_transform([point], mtx)[0]
ValueError: object too deep for desired array
/home/travis/build/matplotlib/matplotlib/doc/examples/api/sankey_demo_links.rst:8: WARNING: Exception occurred in plotting sankey_demo_links
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/api/sankey_demo_links.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 39, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sankey.py", line 732, in add
    tips = rotate(tips)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1671, in transform_point
    return affine_transform([point], mtx)[0]
ValueError: object too deep for desired array
/home/travis/build/matplotlib/matplotlib/doc/examples/api/sankey_demo_rankine.rst:8: WARNING: Exception occurred in plotting sankey_demo_rankine
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/api/sankey_demo_rankine.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 23, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sankey.py", line 732, in add
    tips = rotate(tips)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1671, in transform_point
    return affine_transform([point], mtx)[0]
ValueError: object too deep for desired array
/home/travis/build/matplotlib/matplotlib/doc/examples/pylab_examples/multipage_pdf.rst:8: WARNING: Exception occurred in plotting multipage_pdf
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/pylab_examples/multipage_pdf.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 23, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_pdf.py", line 2424, in savefig
    **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1470, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backend_bases.py", line 2194, in print_figure
    **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_pdf.py", line 2468, in print_pdf
    self.figure.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1079, in draw
    func(*args)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/axes/_base.py", line 2092, in draw
    a.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/axis.py", line 1102, in draw
    tick.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/axis.py", line 249, in draw
    self.label1.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/text.py", line 581, in draw
    self._fontproperties, angle, mtext=mtext)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_pdf.py", line 1855, in draw_tex
    curx, cury = mytrans.transform((elt[1], elt[2]))
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1583, in transform
    return self.transform_affine(values)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1667, in transform_affine
    return affine_transform(points, mtx)
ValueError: Expected 2-dimensional array, got 1
/home/travis/build/matplotlib/matplotlib/doc/examples/pylab_examples/usetex_fonteffects.rst:8: WARNING: Exception occurred in plotting usetex_fonteffects
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/pylab_examples/usetex_fonteffects.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 23, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/pyplot.py", line 577, in savefig
    res = fig.savefig(*args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1470, in savefig
    self.canvas.print_figure(*args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backend_bases.py", line 2194, in print_figure
    **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_pdf.py", line 2468, in print_pdf
    self.figure.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/figure.py", line 1079, in draw
    func(*args)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/axes/_base.py", line 2092, in draw
    a.draw(renderer)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 59, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/text.py", line 581, in draw
    self._fontproperties, angle, mtext=mtext)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/backends/backend_pdf.py", line 1855, in draw_tex
    curx, cury = mytrans.transform((elt[1], elt[2]))
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1583, in transform
    return self.transform_affine(values)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1667, in transform_affine
    return affine_transform(points, mtx)
ValueError: Expected 2-dimensional array, got 1
/home/travis/build/matplotlib/matplotlib/doc/users/transforms_tutorial.rst:115: WARNING: Exception occurred in plotting annotate_transform
 from /home/travis/build/matplotlib/matplotlib/doc/pyplots/annotate_transform.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 14, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1289, in transform
    return self.transform_affine(self.transform_non_affine(values))
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 2259, in transform_affine
    return self.get_affine().transform(points)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1583, in transform
    return self.transform_affine(values)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1667, in transform_affine
    return affine_transform(points, mtx)
ValueError: Expected 2-dimensional array, got 1
/home/travis/build/matplotlib/matplotlib/doc/users/whats_new.rst:1043: WARNING: Exception occurred in plotting sankey_demo_rankine
 from /home/travis/build/matplotlib/matplotlib/doc/mpl_examples/api/sankey_demo_rankine.py:
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sphinxext/plot_directive.py", line 506, in run_code
    six.exec_(code, ns)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/six.py", line 638, in exec_
    exec("""exec _code_ in _globs_, _locs_""")
  File "<string>", line 1, in <module>
  File "<string>", line 23, in <module>
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/sankey.py", line 732, in add
    tips = rotate(tips)
  File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/matplotlib-1.5.x-py2.7-linux-x86_64.egg/matplotlib/transforms.py", line 1671, in transform_point
    return affine_transform([point], mtx)[0]
ValueError: object too deep for desired array
```