New array_cache module
Support 8 texture units in core mesa (now support 8 everywhere)
Rework core mesa statechange operations to avoid flushing on many
noop statechanges.
and state.c file for plugging those functions into the dispatch table.
Don't use Mesa 3.5 for DRI until SGI approves the new dispatch offsets.
Commented-out references to ctx->FogMode and VB->Specular in FX driver.
Minor clean-up in extensions.c
Removed unused prototype in fog.h
