Fortunately, this Paypal module wasn't "super" broken. The errors were just a couple of lines in the templates and a function named patterns() from django.url.conf - urls.py.
This leads into a couple of solutions:
1. I could copy-pasta the code and turn it into a internal django app with the fixes.
2. I could fork it, fix and then setup by own pypi server.
3. I could find out if someone fixed this already and take it from there.
Of course, I'd pick #3 - Programmer. So, lazy. Look it up.
I was lucky to found out that someone has fixed all the issues and got it running on Django 1.10. All that's left is to fork his repo and install it into my virtual environment.
It's simple because pip already supports installing modules from a VCS.
$ pip install git+https://github.com/killertilapia/fixed-forked-project
If you need install a certain branch do this instead
$ pip install git+https://github.com/killertilapia/fixed-forked-project@branch
This also works with other VCS like Mercurial (hg+https), Bazaar (bzr+https) or for-fuck-sakes why! - SVN (svn+https).