[Bf-python] The Point of Point

[Campbell Barton]

noticed Mathutils has a PointObject, but its not used much (at all?) or 
documented,

I cant think of any cases where vectors wont do the trick, so Id be 
interested at the rationale for keeping it in blender
vectors are conceptually a bit different - direction as opposed to a 
point in space but

could we either document and support properly, or remove and  just use 
3d vectors?

in the interest in keeping the API small in maintainable Im happy to 
just use vectors..

- Cam