Semantics of point + vec

[c42f]

Has anyone discussed the mathematical semantics of Point, and how it relates to Vec? This came up in #101, where the mathematical nature of Point might define how Point and Vec interoperate.

Is there a good reason to even have Point and Vec as different concepts? It makes sense to me if Point is meant to be something in an affine space, but as a FSA it's got a whole bunch of operations which don't make sense on points. For example, Point + Point and scalar*Point really don't make a lot of mathematical sense unless you have a blessed origin in your space. If you do have a blessed origin, you actually have a vector space, in which case we may as well be using Vec instead.

To summarize, does Point have a well defined reason for existence, or should we just replace it with Vec?