Fix freetype include path lookup -- don't use freetype-config since it
seems to be broken.  Use that only for version determination.  Warn if
pkg-config is not present.
Merge pull request #3622 from mdboom/freetype-fix

BLD : fix finding "freetype2"
Make sure that the imported qt backend is consistent with selected backend
typo: mp4 -> mpeg4. Closes #3636.
Merge pull request #3637 from WeatherGod/rctypo

BUG/DOC : mp4 -> mpeg4 in matplotlibrc.template

Closes #3636.
Merge pull request #3632 from jenshnielsen/qt_fix

BUG : Fix handling QT_API ENVS
Merge 1.4.x into master