SL-18190 Cleanup -- convert some vec4's to vec3's (as they really are), remove some unused glsl files.

SL-18190 Fix for mystery circle showing up on east side of reflection probes.  Add one probe to rule them all as a fallback for pixels that aren't inside any influence volume.

SL-18190 Fix alpha not playing nice with water surface by split LLDrawPoolAlpha into two passes, one above water, one below water, and clip against water plane.  Currently brute forces two complete alpha passes, still need to cull against water plane and add support for fullbright shaders.

SL-18290

Approved-by: Dave Parks

SL-18190 Use funky distance based error correction only on water surface (revisit for general use later).

SL-18190 Move water shaders to class 3, add debug stub for underWaterF.glsl, make underWaterF and softenLightF apply water fog in linear space.

SL-18190 Temporarily disable occlusion culling by default -- not compatible with depth buffer management changes.

SL-18190 Water shader WIP.  Better parallax correction for sphere probes.  Reduce probe memory footprint.  Remove framebuffer copies and move to deprecate stencil buffer usage.

API expects const char* anyways.

This still needs some work - I'm not super satisfied with the overall structure of the code.  Will continue to iterate as I add in proper RenderDoc support.

SL-18293, SL-18190 -- Fix for debug displays not showing up (wireframe still busted).  WIP on reflection probe/PBR driven water shader.

SL-18239 Unify PBR and non-PBR treatment of ambient/SSAO/irradiance.  Restore SSAO to release version.

SL-18190 End of linear space odyssey -- just eat the conversions in atmosphericsFuncsF for sunlight and additive, but leave linear ambient in tact.