Merge branch 'DRTVWR-559' of https://github.com/secondlife/viewer without protocol changes

indra/llinventory/llsettingssky.cpp

indra/llinventory/llsettingssky.h

indra/llprimitive/llgltfmaterial.cpp

indra/llprimitive/llgltfmaterial.h

indra/llrender/llrender.cpp

indra/llrender/llshadermgr.cpp

indra/llrender/llshadermgr.h

indra/newview/app_settings/settings.xml

...ngs/shaders/class1/deferred/postDeferredGammaCorrect.glsl

..._settings/shaders/class1/windlight/atmosphericsFuncs.glsl

.../newview/app_settings/shaders/class2/deferred/alphaF.glsl

...wview/app_settings/shaders/class2/deferred/pbralphaF.glsl

...pp_settings/shaders/class2/deferred/reflectionProbeF.glsl

...pp_settings/shaders/class3/deferred/fullbrightShinyF.glsl

...wview/app_settings/shaders/class3/deferred/materialF.glsl

...pp_settings/shaders/class3/deferred/reflectionProbeF.glsl

...ew/app_settings/shaders/class3/deferred/softenLightF.glsl

...wview/app_settings/shaders/class3/environment/waterF.glsl

indra/newview/llreflectionmap.cpp

indra/newview/llsettingsvo.cpp