Merge pull request #10 from m45t3r/master

Remove add_mutually_exclusive_group()
adding requirements.txt
Merge branch 'master' of github.com:swong15/shim
Update README.md

Adding how to run instructions
Update README.md

separating out lines for clarity
Modify relative imports to Python 3 style
Fix division

On Python 3 any division results in float, while on Python 2 if you use
only ints you would get a int. Change code to use the correctly //
division, that always return a int on both Python 2 and 3.
Merge pull request #12 from m45t3r/python3

Add Python 3 compatibility, take 2
Create the file when it not exists