Labels: Non-station, non-line ways of adding information to a map

[shannonturner]

I added some of the frameworks for doing this in v7.0 but hid it to give the feature more time.

Essentially, I'd like to be able to add end-of-line markers like WMATA's "RD" and "SV"; see also other metro maps for additional styles that would be very nice to support.

Doing small circles is easiest, but then I need to limit the number of characters in order to keep it looking good, a circle with a lot of text would either 1) overflow or 2) shrink the text, neither of which looks great.

Other cities use rectangular markers which also look nice. There's a lot of different styles I'd like to do, and not just for line markers -- this could be useful for lots of different things.