SL-18453 WIP -- Use GLTF draw pool to render shadows.  Still need a GLTF specific shadow shader to multiply alpha.

SL-18472 Fix for assert when increasing number of texture entries on existing primitive with overrides applied.

SL-17005: Clean up debug code

following promotion of DRTVWR-574

SL-18105 Add mechanism for applying overrides that were received before associated ViewerObject was ready to receive them.

Too many issue were detected after merge, so did a clean remerge of the file.

SL-18105 Hook up live material editor to current selection set and implicitly open build floater when editing a PBR material.

SL-18105 Clean up class1/deferred/materialF.glsl (merge cleanup), make override messaging LLSD where it ought to be and JSON where it ought to be.

# Conflicts:
#	indra/llrender/llgl.cpp
#	indra/llrender/llrendertarget.cpp
#	indra/newview/VIEWER_VERSION.txt
#	indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
#	indra/newview/llfloaterpreference.cpp
#	indra/newview/llviewercontrol.cpp
#	indra/newview/llviewermenu.cpp
#	indra/newview/llviewertexturelist.cpp
#	indra/newview/llvovolume.cpp

following promotion of DRTVWR-548

SL-18411: Copy over LLGLTFMaterial changes (most notably various getters/setters and texture transform stub)

Approved-by: Dave Parks

SL-18411: Copy over LLGLTFMaterial changes (most notably various getters/setters and texture transform stub)