SH-2541 Fix for speckles on avatar on some cards -- don't use "maximum_alpha" for alpha tests in shaders as it was always being set to 1.0 anyway.

SH-2546 Fix for black avatars and terrain on GF Go 7800 (use vec3 instead of float on varying parameters).

SH-2031 Fix for stall in image update -- don't use the CPU to convert a height map into a normal map -- use the GPU instead via a shader.  Also, WTF glFinish?

SH-2447, SH-2525, SH-2276 Strip out defunct global illumination code, add accounting for how much memory is taken up by LLRenderTarget, fix crash on login in bindGLIndices (work around driver bug that doesn't respect VAO state WRT to index buffers), remove some unused render targets, remove some unused shaders, make it possible to run a fullscreen session

SH-2465 Move FXAA to its own pass independent of DoF (also removes the need to reload shaders when toggling FSAA on and off)

SH-2465 Move FXAA to its own pass independent of DoF (also removes the need to reload shaders when toggling FSAA on and off)

SH-2507 Potential fix for basic shaders causing objects to disappear with some drivers (prune shader tree of unused shaders while we're at it)

SH-2507 Potential fix for basic shaders causing objects to disappear with some drivers (prune shader tree of unused shaders while we're at it)

SH-2507 Shave some unused/redundant varying state and make the max texture index debug setting rebuild shaders to use no flow control when set to 1 or lower

SH-2244 changes to run in a core context on AMD hardware without generating deprecation or performance warnings

SH-2243 work in progress -- don't use gl_FragColor or gl_FragData for outputs -- no more deprecation warnings on nvidia

SH-2242 Physics shape display works again, added asserts to flush out areas where state being consumed by a shader does not match state being provided by vertex buffers.

Reviewed by davep.