Fixup for the testing helper for OS X:
- Get NSImage defined.
- Add framework to linking.

git-svn-id: http://google-toolbox-for-mac.googlecode.com/svn/trunk@597 7dc7ac4e-7543-0410-b95c-c1676fc8e2a3
On second thought, drop the OS X support for now.

DELTA=31  (1 added, 29 deleted, 1 changed)

git-svn-id: http://google-toolbox-for-mac.googlecode.com/svn/trunk@598 7dc7ac4e-7543-0410-b95c-c1676fc8e2a3