Feature: accelerators to move ports (counter)clockwise

[andrewschultz]

If we have a connector highlighted, it would be nice to be able to move it around. Like #188, I want to make sure it's sensible before writing up any code.

I like the idea of ctrl-[ for counterclockwise and ctrl-] for clockwise for one of the connectors.

ctrl-alt-[ and ctrl-alt-] could move the other one (counter)clockwise.

Initially, we could just pick the "from" connector as the one that gets ctrl-[, to make sure it works. If the user picks wrong, they user could just push the other one to undo things easily. That would be a proof of concept, but I don't know if it's merge-able code.

I think the algorithm to decide which room doesn't need ALT would simply be

1. whichever is farther north (its center)
2. whichever is farther west (its center) (e.g. in writing order)

This wouldn't be too bad to add, but I'm listing how I would go about doing things.

Additionally, we will trust the user not to make too many overlapping rooms or whatever.

[JasonLautzenheiser]

This works pretty nicely actually as implemented in pull request #190