[Bf-python] BMesh python api proposal.

[bartius crouch]

There are some calc_ functions listed in the wiki. Would it make sense
to have them accept a broader input and then include them in
mathutils?
For example: BMFaces lists calc_area(). This could also be useful for
other cases than just faces. If the function would accept a list of
vectors (and a BMFace for its original function) as argument this
could make it more useful.
However, I realise this might be out of the scope of the api at the moment.

- Bart