Add a function to pretty-print vertex type.

For easier debugging.
Add NOP to GE disasm.
Avoid framebuffer lookups for repeated prims.

There are usually many prims per framebuffer.  This cuts time spent in
SetRenderFramebuffer() from 1% to 0.13% (although a bit more time in
ExecuteOp, not much.)
Avoid calling time_update in GE w/o debug stats.

Just wastes time, especially if the game hammers sceGeListUpdateStallAddr,
which many games do.
Show more vertex type info in the GE frame dump.
Make sure to print all GE command data in disasm.

Even if part of it shouldn't be used, if it is, that may be important.
Merge pull request #1471 from unknownbrackets/gpu-minor

Small optimizations in the emulated GPU