Update of mlab.pca - updated docstring, added saving the eigenvalues.

The old version of pca class did not save the Eigenvalues - just the "fractions" that are just percentage values.

Also added info which row of Wt one can find the Eigenvectors.
Add "sage" colors to colors.py

A Sage user commented that one couldn't make plots in Sage "sage".  But this is a color.  http://xkcd.com/color/rgb/ recommends the following, and the discussion at https://groups.google.com/forum/#!topic/sage-devel/CnH45Ym4zSk indicates it could be useful as well as fun.
Fix #2423: Clip markers off figure.
EHN: add a span_stays option to widget.SpanSelector

If true, the selected span stays visible.
Check if iterator has length

If an iterable is passed into `FuncAnimation` check if it has
`__len__` before trying to take it's length

closes #1769
use GridSpec in plt.subplots

Use a GridSpec object to set up the subplots in plt.subplots.  Add an
optional parameter gridspec_kw.  This enables the user to specify
height_ratios and width_ratios to get grids with unequal row/column
sizes while still having the convenience that subplots provides.
added test for code path where the object passed into `frames` is
does not have a length.
corrected test function name
added test_animation back in to default_test_modules so that the
iterator test actually runs
Fix FancyBboxPatch Typo
don't hard-code class name in representation
Updating regex used to split sphinx version string.

The latest stable sphinx version string is '1.2+'.
The regex pattern '[a-z]' fails to match the '+' character
leading to a `ValueError` being raised when it attempts to
cast '2+' to an int. Replacing '[a-z]' with '[^0-9]' resolves this.
Bugfix for issue #1747. Allows removal of figure text artists.
Merge pull request #2701 from jakevdp/fancybbox_typo

Fix FancyBboxPatch Typo
Adds kwarg `which` to Axis.get_ticklabels, Axes.get_xticklabels,
and Axes.get_yticklabels to match the pattern in other tick-related
functions

Closes #1715
Merge pull request #2703 from androomerrill/plot_directive_sphinxext_fix

Updating regex used to split sphinx version string.
Fix backend_svg.RendererSVG.draw_text to render urls

The SVG backend does nothing with Text object's URLs.  In particular, the rendering path below
backend_svg.RendererSVG.draw_text does nothing with the provided GraphicsContext's _url field.
Merge pull request #2521 from mdengler/svg-text-urls

Fix backend_svg.RendererSVG.draw_text to render urls
Merge pull request #2468 from kcrisman/patch-1

Add "sage" colors to colors.py
Merge pull request #2634 from tacaswell/animation_iter_length

address FuncAnimantion trying to take lengths of generators