Image viewer broken with matplotlib 1.5.x

I opened a cube in glue and dragged it to the main canvas then selected 'image viewer', then got the following traceback:

```
mac-robitaille2:cube tom$ glue L1448_13CO.fits
WARNING: FITSFixedWarning: 'spcfix' made the change 'Changed CTYPE3 from 'VELO-LSR' to 'VOPT', and SPECSYS to 'LSRK''. [astropy.wcs.wcs]
Traceback (most recent call last):
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/IPython/qt/kernel_mixins.py", line 43, in <lambda>
    do_later = lambda: self.call_handlers(*args, **kwds)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/IPython/qt/kernel_mixins.py", line 77, in call_handlers
    self._handle_kernel_info_reply(msg)
AttributeError: 'QtInProcessShellChannel' object has no attribute '_handle_kernel_info_reply'
Traceback (most recent call last):
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/qt/widgets/glue_mdi_area.py", line 60, in dropEvent
    new_layer(layer)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/qt/widgets/glue_mdi_area.py", line 50, in new_layer
    self._application.choose_new_data_viewer(layer)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/qt/glue_application.py", line 562, in choose_new_data_viewer
    return self.do(cmd)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/core/application_base.py", line 145, in do
    self._cmds.do(command)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/core/command.py", line 125, in do
    result = cmd.do(self._session)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/core/command.py", line 215, in do
    v = session.application.new_data_viewer(self.viewer, self.data)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/qt/widgets/mpl_widget.py", line 67, in wrapper
    result = func(*args, **kwargs)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/core/application_base.py", line 71, in new_data_viewer
    c = viewer_class(self._session)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/qt/widgets/image_widget.py", line 59, in __init__
    self._setup_tools()
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/qt/widgets/image_widget.py", line 95, in _setup_tools
    self._tools.append(tool(self))
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/plugins/spectrum_tool.py", line 605, in __init__
    self._setup_ctxbar()
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/plugins/spectrum_tool.py", line 644, in _setup_ctxbar
    self._contexts = [NavContext(self),
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/plugins/spectrum_tool.py", line 156, in __init__
    self._setup_grip()
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/plugins/spectrum_tool.py", line 244, in _setup_grip
    self.grip = self.main.profile.new_value_grip()
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/clients/profile_viewer.py", line 437, in new_value_grip
    result.value = self._center[0]
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/glueviz-0.4.0.dev-py3.4.egg/glue/clients/profile_viewer.py", line 468, in _center
    xy = self.axes.transAxes.transform([.5, .5])
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/matplotlib-1.5.x-py3.4-macosx-10.8-x86_64.egg/matplotlib/transforms.py", line 1584, in transform
    return self.transform_affine(values)
  File "/Users/tom/Library/Python/3.4/lib/python/site-packages/matplotlib-1.5.x-py3.4-macosx-10.8-x86_64.egg/matplotlib/transforms.py", line 1668, in transform_affine
    return affine_transform(points, mtx)
ValueError: Expected 2-dimensional array, got 1
```

@ChrisBeaumont - I can look into it, but first wanted to check whether this is a known issue and whether you've already identified the cause?