Add tile painting hotkeys

[dfb]

(another ticket broken out from #4)

It might be nice to be able to rapidly switch among tile painting tools via hotkeys. One possible way to do it:

• The number keys 1-3 select a tool in the type, lighting, and movement rows, respectively
• Pressing the same number again cycles to the next tool on that row, wrapping around to the front if needed
• Pressing shift + the same number again cycles in the opposite direction

Example: water is currently selected and the user taps '3', so it jumps to the first item in the movement row

Example: water is currently selected and the user taps '1', so it moves to forest (or whatever is next in the tile type row)

Possible variation that might be a terrible idea: when moving among rows, instead moving to the first one, move to whichever one was previously selected on that row.