Attempt to switch U.F.O. output so as to use libxml2.
Merge branch 'master' into ufo_libxml2_1
Zero-terminate where necessary.
Fix a few things.
Fix entity names.
More names and indentation.
Fix hierarchy.
Merge branch 'master' into ufo_libxml2_1
Fix an infinite loop that would never run anyway.
Implement xmlSetPropPrintf and reduce code as possible.
Remove now-unused code.
Fix off-curve point placement.
Fix hint placement.
Fix hint hierarchy.
Update comments, remove cancelled TODO items, remove dead code.
Merge pull request #1408 from fontforge/ufo_libxml2_1

Switch to libxml2 for output of glifs and plists in the U.F.O. driver.