[coretext] Use CGFont as face_data
[coretext] Fix assert on Yosemite

Apparently those functions documented as sometimes returning NULL
actually exercise that right in OS X 10.10 Yosemite.  The scratch
was too small for that.  I *think* I fixed it, but haven't tested
as I don't have Yosemite.
Minor
[wince] Try to fix some stuff on Windows CE

Based on errors seen here:
http://testresults.qt-project.org/ci/QtBase_dev_Integration/build_03837/wince70embedded-armv4i-msvc2008_Windows_7/log.txt.gz

Fully untested.