Bug 1060198, part 1: Remove IS_GYP_DIR's replacement of INCLUDES, r=glandium.

--HG--
extra : rebase_source : 4f322f0b9d57f108815f2aa4b689d2dc01b4e4e7
Bug 1060198, part 2: Move other IS_GYP_DIR rules to gyp_reader.py, r=glandium.

--HG--
extra : rebase_source : 5ad6eae63688f5582568f470b7266b0f7ebc8b6c