Also add a test that freetype-go derives the same glyph points as
the C freetype implementation.
R=bsiegert
CC=golang-dev
https://codereview.appspot.com/12670046
This is a manual hg commit of codereview change 982044
http://codereview.appspot.com/982044
The codereview submission did not work, possibly because some of the
files were too large.