BUG: viz: black background in PDF and SVG output
Remove trailing print
DOC: correct docstring
ENH: make it easier to use axes in slicers
COSMIT: nicer vizualization example
MISC: remove transparency

Using transparency is a bad idea because if you save as figures as PDFs,
the corresponding PDFs will rely on transparency in PDF which
cannot be translated to EPS (EPS does not have the notion of
transparency). As a result, publishers like Elsevier will rasterize the
figure, often in a very crude way. People keep getting bitten by this
effect. It is better to change the defaults.
Merge remote-tracking branch 'gael/viz_black_bg' into main-master

A set of small fixes to plotting:

* black-bg now works with pdf/svg outputs
* removed a debug print
* docstring fixes in plot_anat/plot_map
* minor tweaks to make it easier to specify axes
* remove default transparency for compatibility with EPS

* gael/viz_black_bg:
  MISC: remove transparency
  COSMIT: nicer vizualization example
  ENH: make it easier to use axes in slicers
  DOC: correct docstring
  Remove trailing print
  BUG: viz: black background in PDF and SVG output

Conflicts:
	examples/labs/need_data/viz.py
DOC: fix typos in visualize
BF: make example compatible with Python3

Print statement; use of __doc__
DOC: remove copyright symbol from argparse

It broke the 2to3 doctest fixers for Python 3.3
BF: recythonize pyx files for Python 3.3

Python 3.3 complains about attempted relative imports for older Cython
.c files; newer Cythons generate code that fixes this.
NF: make target to recythonize pyx files

Run cython on all found .pyx files.
DOC: update Changelog for 0.3 release
NF: add script_test label to tests for scripts

Using this to debug why the script tests are failing using the nibabel
sdist tester.
DOC: update release instructions for script tests

I needed to change the automated script tests in nibabel to accomodate
the script tests in nipy.
DOC: update surrogate array docs / docstrings

The API seems to have changed a little; update imports and
documentation  Fix docstrings for sphinx errors.
DOC: minor rejigging of enn doc / docstrings

There were confusing sphinx errors for the ``enn.rst`` file.  Some were
solved by upgrading Sphinx from 1.0.3 to 1.1.3; the docstring edit
solved a couple of indentation errors.
DOC: updating doctests sphinx docs

Doctests are all now passing on my box, but with some extra changes in
the code, that I will submit as a separate pull request. Basically I
needed to allow objects for coordinate map coordinate types to allow the
sympy things that Jonathan is doing in the long coordinate map
discussion.
TST: remove yields in coordinate_system tests

Remove use of generators in tests to make them easier to debug
RF: allow object coordinate in coordinate system

Objects as coordinate values can be useful for sympy expressions as
coordinates.  Objects can often be subtracted, compared etc.  In fact we
already use objects as a coordinate type in the documentation.