WIP mackup 0.5.9 with python setup.py

Hi,

I'm trying to switch the formula of mackup from a bare copy of file to a cleaner one using the `setuptools` way.
But I'm hitting a wall.

I'm using this branch Mackup: https://github.com/lra/mackup/tree/app_structure

The goal is to have a very small `mackup` script calling the `main()` function of the `mackup` module.
So ideally `python setup.py install --prefix=#{prefix}` should install `/usr/local/bin/mackup` pointing to `/usr/local/Cellar/mackup/0.5.9/bin/mackup` and the module in `/usr/local/Cellar/mackup/0.5.9/lib/python2.7/site-packages/`
It works when I do `python setup.py install` locally.
But when I `brew install` this formula, it complains:
```
Checking .pth file support in /usr/local/Cellar/mackup/0.5.9/lib/python2.7/site-packages/
/usr/bin/python -E -c pass
TEST FAILED: /usr/local/Cellar/mackup/0.5.9/lib/python2.7/site-packages/ does NOT support .pth files
error: bad install directory or PYTHONPATH
```

I guess that's legitimate, but how can I make my little `bin/mackup` script call the rest of the code in the `mackup` package if I can't install my package in the homebrew `PYTHONPATH` ? Or if the Cellar `site-package` path is not in the `PYTHONPATH` ? Should I give up on the `setuptools` way ?

`Mackup` is not on `pypi` and I don't want it to be there.

I might mix things up here and might be doing something stupid, but I can't find any help in the doc. Any help on this ? Or any pointer ?

Thanks a lot !

ps: I'll clean up the formula once I have a solution to this problem.