Check input columns are not reserved names

[LamAdr]

Hi @vincentarelbundock , this should fix #90 I added all columns that might be returned by all three main functions in the reserved_names set. However, I am afraid this will block unproblematic situations, eg when it turns out that the problematic column is not used by pymarginaleffects. I don't see a simple way to filter these columns out of the check.

Thank you

[LamAdr]

@vincentarelbundock ready for review

[vincentarelbundock]

Thanks!