Handling non-finite forms

[epageperron]

It would be best to add a rule to handle non-finite forms.
Right now we mark finite forms this way :
"Verb Form": {
"FIN": "Fin",
"FIN-L1": "Fin",
"FIN-L2": "Fin"
},

The rule should be:
Only in the case of verbs ( V ), if there are no prefix before the POS, except "nu", then verb form is non-finite, it should be marked at "Part". If there is one or more prefix, then it is finite and should be marked at "Fin'". In the case of V with no prefix but followed by PF, the "Ger" tag should be used.

http://universaldependencies.org/u/feat/VerbForm.html

(cc: @lukurkurra )

[epageperron]

Finally we added a tag for non-finite forms.
the presence of NF marks the V as non-finite. All other V forms are finite.

[epageperron]

@jayanth @sagar are these new tags we added currently handled properly in the converter to conll-U? I imagine it would require mapping to UD ??