mips: Initial structure for a MIPS emitter.
mips: Add some basic jumping and logic instructions.
mips: Add basic load/store for the MIPS emitter.
mips: Add a basic MIPSXCodeBlock.
mips: Duh, oops.  LUI is one reg, of course.
Integrate new MIPS emitter.
Implement a MipsJit.
Add some more MIPS instructions
mips: Clean up MIPSXEmitter a bit.

Don't even want dangerous funcs like SUB().

Keeping things in opcode order at least locally so it doesn't get
confusing to maintain.  Also fixed a bunch of missing asserts.
mips: Add helpers for constant loads.
mips: Add JALR/JR.  QuickCallFunction should link.
mips: MIPSX -> MIPS.
Merge pull request #7098 from unknownbrackets/mips-emitter2

Initial MIPS emitter