Revisit math notation for points and vectors

[hollasch]

Peter's latest idea: uppercase for points, lowercase for vectors.

[hollasch]

So I think the following works:

• Points: uppercase bold non-italic
• Vectors: lowercase bold non-italic
• Other variables, including scalars, are italicized
• No vector barbs used anywhere

[trevordblack]

I noticed some inconsistencies in points/vector/etc. in my pass, I'll continue to mark them up in #333, but should I hold add off adding a commit with those changes?

[hollasch]

Probably merge PR #483 into your changes.

[hollasch]

Done in PR #483