Some minor cleanups for error handling/printing types correctly
Add exponentiation operator
Add binary-trees benchmark, also from PL shootout. We're super slow at this one!
Add is_control_flow_op to asm.mg
Add sum builtin
Tiny benchmark output formatting cleanup
Better error messages for getitem failures
Add functionality to asm.mg to detect non-modifying instructions (cmp, test, anything else?)
Fix infinite recursion in getattr error message, in a somewhat horrifying way
Add basic loop-free SSA support to regalloc.mg. Perhaps bugulant?