SH-2276 Fix for TDR's on GTX 460 et al -- don't use texture units above 16 (workaround for prevalent driver bug)

EXP-625 Speed up initial outfit copy and avatar bake by moving initial gesture copy to LLAppearangeMgr::onFirstFullyVisible().

EXP-625 Subtle change to get the initial avatar on the screen a little faster, then get to the gestures.

EXP-625 No longer stuck as a cloud on initial login by fixing logic around fetching library items from the Inventory capabilities.

Changed covenant and debug panes per Oz's request.
Covenant is taller; Restart buttons are moved to the right.

SH-2240 WIP on removing lots of string comparisons that were added to deal with exploding amounts of non-built-in GL state

SH-2488 Fix for shiny and alpha not interacting well on rigged attachments (and fix for assertion when rendering model import preview)

- don't use F64 except where needed (should really factor out calls to gluProject)
- get rid of sorting by texture in favor of sorting by matrix (no sort needed, geometry is already matrix sorted as a result of frustum cull tree traversal order)
- unroll matrix sync inner loop and cache MVP and normal matrices