Feature/gehana

[whaeck]

This PR removes the hana coding for enumerated files and the material object for easier integration on the Python side.

Where necessary (i.e. for the enumerated MF1, MF2, MF7, MF8 and MF32), convenience constructors were added to the C++ and Python interfaces.

Food for thought:

• do we want insert(), insert_or_replace(), remove(), etc. functions on the parsed objects as well (reflecting the interface on our tree components)

[whaeck]

7 months waiting for a review. I'm admin merging this to get it over with.