Add setup.py

[obust]

You should add a setup.py script so COMBO can be pip installable

Here is some resources:

• https://docs.python.org/3/distutils/setupscript.html
• https://github.com/pypa/sampleproject/blob/master/setup.py

Also note that by convention, packages and module are lower case.
So ideally it would be: import combo instead of import COMBO