Fix direct light matching across alpha/blended-material/deferred.

Get diffuse lighting to match from Low to Ultra.

NORSPEC-349 make render targets use original formats when resizing impostors and fix alpha for deferred impostor shader

replace llinfos, lldebugs, etc with new LL_INFOS(), LL_DEBUGS(), etc.

MAINT-2370 Add debug setting "RenderAutoMuteRenderCostLimit" that automatically visually mutes avatars above a certain threshold (adjusted by Avatar Mesh Detail Slider)

MAINT-616 Factor out calls to glGenFoo where possible, add setting to control synchronizing strategy WRT occlusion queries, add experimental transform feedback driven LoD update

SH-2084 Don't error out on framebuffer mismatch -- probably causing a crash when some post-snapshot or minimize/restore operation gets out of phase.

SH-2447, SH-2525, SH-2276 Strip out defunct global illumination code, add accounting for how much memory is taken up by LLRenderTarget, fix crash on login in bindGLIndices (work around driver bug that doesn't respect VAO state WRT to index buffers), remove some unused render targets, remove some unused shaders, make it possible to run a fullscreen session

SH-2276 Fix for failed assertions reported from debug-enabled viewers.  Also, remove "Basic Shaders" as a user settable option (shaders are always on if GL version >= 2.0, always off otherwise)

SH-2244 Don't use multisample texture (ever), and don't use GL_DEPTH_COMPONENT32 (use GL_DEPTH_COMPONENT24)

Reviewed by Leslie