Fix for bad fullbright shiny shininess values and inconsistency between materialF and fullbrightShinyF

SL-12005 Fix for projectors getting brighter when switching to single light shader.

SL-12781

Approved-by: Dave Houlton <euclid@lindenlab.com>

SL-12784 disambiguate vertex_color.a of 0

SL-12850

Approved-by: Dave Houlton <euclid@lindenlab.com>

SL-12233 Fix for disagreement between fullbright implementations with ALM on and off.

SL-12781 Remove expensive and redundant z clear; instead enable/disable z test for background and model preview

SL-12781 Cleanup: Remove HACK / MAGIC NUMBER effective constant of mCameraDistance as it is set in setPreviewTarget() via initModelPreview()

SL-12784 restore vertex color alpha contribution

SL-12171 Fix emissive mask being too bright post sRGB/Linear cleanup

SL-12592 prevent unintended opaque-ification of alpha-blended materials

SL-12574 Fix EEP cubemap not matching non-EEP for both ALM on and off

Approved-by: Dave Houlton <euclid@lindenlab.com>

Fix for mismatch on angular attenuation between sunlight on opaque and transparent objects from last commit.

Fix for mismatch on angular attenuation between sunlight on opaque and transparent objects from last commit.

Fix for sunlight having improper gamma curve for angular attenuation.  Fix for lack of angular attenuation on ambient lighting on triangles facing away from sun.

Fix for sky in wrong color space.

Davep/BUG-228263

Approved-by: Dave Houlton <euclid@lindenlab.com>

Fix for under water being much brighter and mismatching between alpha and deferred.  Don't make terrain fullbright under water.

WIP - Windlight sun lighting should happen in sRGB space, not linear space.  This keeps ambient from getting overblown and better matches environment lighting with ALM on/off.