Add GDEF support.

Adds src/gdef.{h,cc} for GDEF table support.
This CL also adds src/layout.{h,cc} that implement utility functions for OpenType layout common table formats.

BUG=27131
TEST=ran test_{,un}malicious_fonts.sh for 4500+ OpenType fonts.


git-svn-id: http://ots.googlecode.com/svn/trunk@49 a4e77c2c-9104-11de-800e-5b313e0d2bf3
8 files changed