AltForm & Form & Forme => Form
GenNumber & Generation => Generation
Extract out SpeciesForm interface, and re-add IGeneration
For those using PKHeX as a dependency, this should be a pretty straightforward manual replacement... GenNumber and AltForm should be quick find-replace`s.
all but egg exposed it; now, just make egg expose it and remove the unnecessary interface
we still need to Set generation for non-eggs/mgift, so have a separate Settable interface for internal purposes.
