The `__future__` we relied on is now, where the 3 specific things are
all included [since Python 3.0](https://docs.python.org/3/library/__future__.html):
* absolute_import
* print_function
* unicode_literals
* division
These import statements are no-ops and are no longer necessary.
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`
