Increase the reporting message buffer a bit.

Although, I'm not sure it's actually being hit.
Detect EXT_gpu_shader4 to use bitwise ops pre-3.3.

This may allow it to work on more cards, and should fix a (probably driver
bug) error we've had reported in GL 3.0 / GLSL 1.3.
Merge pull request #6831 from unknownbrackets/glsl-int

Try to use bitwise / texelFetch in glsl based on EXT_gpu_shader4