Both pass through linear RGB similarly, but sRGB should be faster.
If both are enabled, the .cgp author won't need float32-only features like
packing multiple values. This also makes testing/usage priority the same.
Add sRGB FBO logging to mirror float FBO logging.
Make LUT mipmapping consistent with FBO's (ignore it for magnification.)
Fixed a bug where "Apply Shader Changes" in RGUI saved/set the wrong
texture filter for LUT textures.
Unofficially extended Cg shader spec with an LUT mipmap option:
To mipmap LUT "foo," add 'foo_mipmap = "true"' to your .cgp/.glslp file.
Mipmapping is currently implemented for the OpenGL driver only.
