Split up cmpcodesize script into a package, with a main.py file that
acts as an entry point to the program. The functions that use otool to
actually determine binary size have been moved into compare.py.
Note that to execute cmpcodesize, you may now run either:
1. `utils/cmpcodesize/cmpcodesize.py`
2. `python utils/cmpcodesize/cmpcodesize/main.py`
