- Optimized size of get_global machine code
	- add $os to ir/ast.d
	- add alias in lib/ffi for $os
	- add test for ffi.os
Merge branch 'master' into ffi.os
	- switch ffi.os to use string from util/os.d
- Implemented soft-spilling for get_global
- Added new GC test
- Fixed GC bug wrt undefined global exception
- Modified spillTestFn to pass along LiveInfo
- Optimized LoadOp, removed redundant move
- Removed redundant register saves in alloc ops
- Added image library test
- Optimized comparison branches
- Optimized IsTypeOp
- Optimized set_str
- Optimized map_prop_idx
- Fixed issue with freeReg()
Merge branch 'master' of github.com:maximecb/Higgs into dev-maxime
Merge pull request #95 from teebrz/ffi.os

ffi.os