Add gyp support for Core Data datamodel (*.xcdatamodel) files
Add gyp support for Core Data datamodel (*.xcdatamodel) files

Contributed by kanefsky@gmail.com
Cloned from:
http://codereview.chromium.org/11275067/

BUG=303
TEST=Verify xcdatamodel files are editable in xcode project.
TBR=mark@chromium.org
Review URL: https://codereview.chromium.org/11367037
old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google