Refactored and updated map4 so that it can be used as a Pypi package

[LucaCappelletti94]

I have refactored the package, documented it more and generally made it presentable as a Pypi package.

I have also published the package on Pypi, to make it easy to use. @alicecapecchi if you'd like to be made maintainer of the package on Pypi, send me your Pypi username and I will add you immediately.

I have removed all dependencies to tmap, as it no longer works, as noted in several issues. At least, not the version that can be easily installed from Pypi.