ROADMAP Fadin 0.2 release

[tomMoral]

TODO before releasing Fadin 0.2

• Change API to feed in events as pd.DataFrame (PR ENH expect pd.DataFrame as input of FaDIn.fit #15 )
• Remove unused parameters from the API (PR condense init parameters #16 )
• Add the possibility to learn with marks.
• Add UnHap solver (in a file solvers/unhap.py).
• Add examples for UnHap
• Decide if we change the name for the package.
• Add random_state argument to FaDIn init.