Add ScalaFunctional

[EntilZha]

I am the author of a package at https://github.com/EntilZha/ScalaFunctional which is on pip via pip install scalafunctional. I specifically have pypy on my TravisCI build so would be great to get added here.

[xando]

Hey @EntilZha,

The PyPy team is getting closer to the next big release, along with it will update a pypy.packages as well. The plan is to add an option with custom / extra packages that are not in 1000 pypi.