Fixes issue #2525: clears _suptitle instance on clf() and fixes a bug
where suptitle endlessly adds text artists to the figure
Merge pull request #2711 from cimarronm/figure_suptitle_fix

Remove suptitle on clf.
Merge pull request #2239 from blackw1ng/patch-1

Update of mlab.pca - updated docstring, added saving the eigenvalues.
Merge pull request #2423 from mdboom/cull-off-of-figure-markers

Off-axes markers unnecessarily saved to PDF
Merge pull request #2481 from mdboom/datestr2num-fix

datestr2num of year and month fails on 29th, 30th, and 31st of month
Update widgets.py

removed whitespace
Improvements to anchored_artists.AnchoredSizeBar

Fix: color argument was not setting the color of the textlabel
Add: setting the font-size through the fontsize argument
Add fontprop parameter to anchored_artists.AnchoredSizeBar

Removed the old fontsize parameter.
And fix: some typos in the example in the docstring
Updated @megies' PR to include a test and some other tweaks.
Merge pull request #2248 from leejjoon/axes_grid1_axes_aspect_fix2

axes_grid1: ImageGrid respect the aspect ratio of axes.
Autopep8 on testing.compare
Manual PEP8 fixes.
Final tweaks to compare.py for full PEP8 compatibility.
Deprecated matplotlib.testing.image_util.
Add cleanup to test
Removed commented-out portions
Fixed LogFormatterExponent to correctly format negative exponents and added tests
Make LogFormatterExponent tests check more non-integer ticks and bases
Added missing cleanup decorator import.
Package initialization made possible when executed in environments whithout access to the home directory.

Functions _get_xdg_config_dir(), _get_xdg_cache_dir(), _get_config_or_cache_dir() allow now the use of the environment variables XDG_CONFIG_HOME resp. XDG_CACHE_HOME without requiring access to the home directory (f.ex. in batch jobs on clusters).

Before, the definitions of the environment variables would not have been used when the home directory was not accessible. Nevertheless, the standard does not bind the variable definitions to the existence of home directories (only the default values are defined with respect to them).