axes_grid1: ImageGrid respect the aspect ratio of axes. This addresses #955
Add default kwarg to datestr2num to fix #2481
Use mpl.checkdep_ghostscript function to find ghostscript
Fix Tk keyboard modifier masks on Windows
Merge pull request #2693 from cgohlke/patch-1

Use mpl.checkdep_ghostscript function to find ghostscript
Merge pull request #2696 from cgohlke/patch-3

Fix Tk keyboard modifier masks on Windows
Merge pull request #2481 from mdboom/datestr2num-fix

datestr2num of year and month fails on 29th, 30th, and 31st of month
Merge pull request #2248 from leejjoon/axes_grid1_axes_aspect_fix2

axes_grid1: ImageGrid respect the aspect ratio of axes.