`README.md` in each crate

[ytanimura]

Consider for README.md in each crate cf. README.md by virtualritz

[MattFerraro]

I would love to see a readme that describes in a few sentences the primary data types and when you're supposed to use which ones. There seems to be a few like Vector3, Point3, Vertex, which all seem similar. There's also things like Edge and Wire and Line, and I'm not sure when I should use one over another.

[ytanimura]

Thank you for your comment.

Would it be sufficient to write something similar to the beginning of the truck-topology document in each crate README?