SL-12902 Fix for doing the technically correct but compatibility wrong thing WRT light color values.

Ifdef'd code for potential skinning speed up to avoid lots of int<->float conversions (expensive and static for min space investment)
as updating rigged VBs shows up as a profiling bottleneck for Low rendering (where we actually use CPU skinning).

Provide method of storing joint indices sep from weight data for faster runtime processing.

Soften assert on non-finite data in LLCoordFrame until we can isolate conditions to repro the assert.

Tamp down more view-dependent refraction map fail.

Will wait for a response from @graham_linden regarding moving the sRGB conversion functions in llmath.h to llrender.

Make sure lights are in the correct color space.
Bonus: cache the sRGB color in setLightColor on point and spot lights.  Frees up a pow and some multiplies on the CPU every frame.

Thou shall always read the sky cubemap as sRGB using hardware sampling.

Mods to make merge with viewer-release have less whitespace-only change and fix diffs between EEP and VR.

Fix water rendering causing distortion map update very frame.

Reduce binds in alpha draw pool for HUD atmo suppression (may regress HUD lighting weirdness).

Add ability to retrieve current user clip plane so it can be saved/restored around water map gen.

Leave render type masks as is after reflection map render to get detail filtering applied to distortion map again.

Re-enable occlusion in distortion map rendering.

Silence launcher warning for devs.

Work-around path gen deciding to gen NaNs for some flexi prims.

Fix class2 softenLightF shader.

Remove Matrix3/4 funcs using LLQuat 4-float init incorrectly
(they are redundant to angle/axis versions anyway).

Fix up tests referring to removed funcs above.

Modify autobuild.xml to use new libatmo w/ state save/restore fixes (addresses font render glitch).

Put in nSight debug support.

libatmosphere integrated in indra/llrender/llatmosphere.cpp

Still working on runtime shaders to use libatmosphere precomputed atmospherics textures