Fix trying to bind diffuse maps for shader without uniform in shadow shaders.

Clean up merge fail around mShaderLevel namechange.

Water plane rendering improvements

Approved-by: Graham Madarasz <graham@lindenlab.com>

[WIP] Use EXT_texture_sRGB_decode in order to selectively sample textures consumed by the deferred renderer as sRGB

Approved-by: Graham Madarasz <graham@lindenlab.com>

This is more or less to achieve the non-ALM bloom behavior in most circumstances.
Why scale it?  Normalized blinn-phong gets brighter the higher the specular exponent.  As it stood, the old spec contribution was extremely bright despite looking "correct".  This is largely eyeballed, but generally looks better for all light sources applied to the surface of the water.

The atomospherics were being applied both in the G-buffer and during the sun light pass.  This ensures that is not the case.
Additionally, re-enable specular on the water plane, scale the bloom factor to something more reasonable, and also someone broke specular on emissive surfaces.  That's fixed too now.

Enable RenderAlphaBatchEmissives by default to get some perf back.

Add Geenz doings to the contribs list.

Fix per-frag atmospherics to use sRGB conversion.

Update ref to new KDU package.

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

SL-10766 and SL-9650

Approved-by: Andrey Lihatskiy <andreylproductengine@lindenlab.com>
Approved-by: Rider Linden <rider@lindenlab.com>

SL-10833 FIXED [EEP] Text in the Sky Altitudes boxes is low contrast and difficult to read.

Approved-by: Andrey Kleshchev <andreykproductengine@lindenlab.com>

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.

Make moon brightness env setting affect moon diffuse/ambient color combo so it affects in-world lighting.

Adjust how the moon brightness affects the moon disc texture rendering (washes out less).

Replace old spot prio calc.

Replace fudge factors on light radius and falloff for deferred lights.

SL-10818 FIXED [EEP] Wrong selection when keyframes are close together

Approved-by: Andrey Kleshchev <andreykproductengine@lindenlab.com>

Make moonlight darker and slightly bluish for scotopic feel when moon is primary.