dd vhea/vmtx table support.

- Added vhea.{cc,h} and vmtx.{cc,h}.
- Added metrics.{cc,h} to integrate common functions of hhea/hmtx and vhea/vmtx.
- Moved functions in hhea.cc to metrics.cc.

BUG=77386
TEST=http://code.google.com/p/ots/wiki/HowToTestOts (verified with 3500+ font files)
TEST=test/table_dependencies_test.cc


git-svn-id: http://ots.googlecode.com/svn/trunk@61 a4e77c2c-9104-11de-800e-5b313e0d2bf3
15 files changed