Reject non-ASCII characters in shader source at the preprocessor level.

Reject non-ASCII characters in shader source at the preprocessor level.


Committed: http://code.google.com/p/angleproject/source/detail?r=545

[kbr1, 2011-01-28 21:02:15]

This fixes an issue reported by cevans separately.

Verified with his test case; the new error is raised when encountering shaders
containing identifiers with non-ASCII characters. Did not test with shaders
containing non-ASCII characters in comments. Tested with WebGL content and
verified no other effects.

[dgkoch, 2011-01-28 21:04:34]

LGTM