A bit of simplification of rex prefixes
Add one's complement support to bootstrap
Add sarx/shlx/shrx
Add multi-arg range
Add xor operation to Integer, should've been there before...
Add a small framework to asm.mg that generates test instructions with more variety
Fix a few asm.mg bugs fleshed out by the new test framework
Add diff output to tests/raw/asm.py, to make finding asm.mg bugs a bit easier