Adjust ambient clamp up to get closer match to release viewer for existing content.

Don't short-circuit getVisibleExtents as its side-effects are relevant.

Reduce spec bloom further.

Modify calc of sunlight to avoid clipping in gamma correct on values outside 0-1 range.

Modify shaders to put back ambient clamp tuned to be close to ambient contrib in low/mid lighting.

Fix merge error

SL-9684 Fixed editor edits environment that was freshly applied from same editor

Approved-by: Maxim Nikolenko <maximnproductengine@lindenlab.com>
Approved-by: Andrey Lihatskiy <andreylproductengine@lindenlab.com>

SL-10996, SL-11149

More shader tweaks to fullbright transport to get correct coloring while keeping fog fixes.

Restore old sun matrix gen code.

Make sky use correct colorspace.

Make sunlight color the CPU-generated WL color when not using atmo shaders or deferred (helps 11107).

SL-11149

Fix fullbright colorspace handling and atmo transport.

Make OpenGL 3.3 cards not false alarm on version 140 shader reqs.
Makes deferred rendering work on low-end GPUs more often.

Fix alpha mask shadows to mult vert alpha prior to discard tests and obey min alpha settings.

Make shadow/shadowAlphaMask use consistent varying and output.

Also fixes bug with 0% and 1% transparency providing varying different visual results.

Remove tweaks to combine cascade results.

Re-fix sun/moon glow factor and make it depend on moon brightness.

Make cloud shaders use sunlight color exclusively for consistency when moon is up or down.

Make haze look more like WL.

Make lack of sun and moon mean black and fixed dir to prevent spooky underlighting.

Fix diffuse boost in deferred lighting to match non-deferred.

Make class2 soften not clamp shadow color to incoming alpha (make shadows appear on terrain underwater).

Tweak DistortionWaterClipPlaneMargin (1.0001 -> 1.0125) to mask edges of objects in water disortion map.