REL: v2.2.2 LTS

The second bug-fix release of the v2.2 LTS series.

This release fixes a number of critical bugs from 2.2.0:

 - restores matplotlib.verbose (fixing embedding in pycharm)
 - preserve precision when color mapping small portions of data with
   extreme outliers
 - fixes saving long movies with ffmpeg
 - fixes UnbourdLocal error in contour labeling
 - fixes import failure on python 3.4.0 and 3.4.1
 - fixes compile time failures with clang on 32bit platforms
 - fixes an icon in the Tk backends
 - fixes several issues with Tables
 - fixes expanding offset boxes with tight_layout
 - revert changes to the font caching to avoid a possible bug in
   backports.lru_cache
 - numerous docstring and documentation fixes

We have reverted the deprecation of `font_manager.TempCache`.