Update Axes3D.tricontour for custom triangulations

An example has also been added to illustrate the additional flexibility
possible with providing a user-defined triangulation.
Make Axes3D.contourf take arbitrary triangulations
Add Axes3D.contourf example
Update changelog/whats_new for 3D tricontour plots
Typos
Add EXPERIMENTAL note to Axes3D.tricontour[f] docs
Fix compilation on Solaris
color of candlestick lines

the line of a candlestick should have the same color as the body (rectangle)
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.
axes_grid1: ImageGrid respect the aspect ratio of axes. This addresses #955
BUG: Fixed github stats retrieval

Currently urllib is used to retrieve a json file from Github, however
Github url used is not static url, urllib2 required to retrieve
information from Github.
Fix bugs related to bottom kwarg in step histograms

Conflicts:

	lib/matplotlib/axes.py
	lib/matplotlib/tests/baseline_images/test_axes/hist_step.png
Bug: alpha parameter was ignored when fill color is #000000
BUG: Fixed object type missmatch in SymLogNorm

Currently SymLogNorm accepts both linthresh and vmin, vmax with their
native dtype, meaning that the contents of one object cannot be updated
with another due to a mismatch of types.
Alternative to #2431: Decode the filenames returned from fontconfig in
the filesystemencoding.  Fix a number of buglets that did not allow
fonts with non-ascii filenames to be opened.  This involves taking
advantage of code already in FT2Font to use unicode filenames, and
encoding the filenames before passing into ttconv.
Just skip a file if its filename can not be decoded
Added check in autoscale_None for completely masked pcolor plots.
Fix MacOSX backend post-six transition
Use the --format argument to fontconfig so we don't have to parse
anything complex ourselves.
Fix failing mathtext tests.