SH-2591 WIP -- fix for UI disappearing, introduces some artifacts in rotation ring, committing to debug elsewhere

SH-24114 Remove unused vectorization code (outdated/unused with SSE2 requirement and llvetor4a et al)

SH-2652 Fix for black bands in high-res normal maps (break normal map generation up into tiles to handle the case where a normal map is higher resolution than the current window)

SH-2652 Slightly slower DoF (quality), apply FXAA *after* DoF, fix for some render targets not getting allocated when needed.

SH-2541 Fix for speckles on avatar on some cards -- don't use "maximum_alpha" for alpha tests in shaders as it was always being set to 1.0 anyway.

SH-2546 Fix for black avatars and terrain on GF Go 7800 (use vec3 instead of float on varying parameters).