SL-20611 Make haze effect local lights -- move sky and water haze to their own passes and unify sky and water haze in forward rendering shaders.

SL-20440 Fix for projector ambiance destroying PBR shading.  Also fix longstanding bug with hard line in projector ambiance lighting.  Incidental decruft of legacy_adjust and LOCAL_LIGHT_KILL, etc.

DRTVWR-559 Revert skies to be very close to release and disable tone mapping when probe ambiance is zero.

Hack for desaturating legacy materials has been removed for performance and quality reasons.

Adds a new setting for auto adjusting legacy skies.  This is the PBR "opt out" button.  If disabled, legacy skies will disable tonemapping, automatic probe ambiance, and HDR/exposure.  If enabled, legacy skies will behave as if probe ambiance and HDR scale are 1.0, and ambient will be cut in half.  

HDR scale will act as a sky brightener, but will automatically adjust dynamic exposure so the sky will be properly exposed.  If you want relatively even exposure all the time, set HDR Scale to 1.0.  If you want a high range of exposures between indoor/dark areas and outdoor/bright areas, increase HDR Scale.

Also tuned up SSAO (thanks Rye!).

Reviewed with Brad.

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

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

SL-18190 WIP -- Take 2 on linear space windlight (more methodical approach -- make desired interface but brute force color conversions). Placeholder PBR water and move to deprecate forward rendering shaders.

SL-14113: Remove magic numbers. Take advantage of existing shader #defines injection by extending shader loading to make use of addConstant() instead of hard-coding magic number constants in each GLSL file.

SL-14113: Remove magic numbers. Take advantage of existing shader #defines injection by extending shader loading to make use of addConstant() instead of hard-coding magic number constants in each GLSL file.

SL-14731: Fix sun gamma -- merge Sovereign Engineer's patch: Fix sun gamma space for accurate color reproduction of sun textures

Removed some potential div-by-0 NaNs and a mangled clamp.

Had to find a balance in the sunlight intensity calculation that behaves correctly for
both these issues.