Cleaned up the hotkeys file.

Removed lots of old duplicates, fixed `cmd-O`.
Refactored hotkey declarations into respective tool classes.

Hotkeys should be declared from within each listening class, if
possible.
Fixed `hover` and `uncover` events for topUI

Previously, topUI was never properly sent these events in all cases.
Added tooltips for tools.

Currently defined via raw html, just like menus.
Removed some silly extra key bindings.

The actual binding are in the menu items.
Merge branch 'hotkeys+tooltips' of https://github.com/Fishrock123/mondrian into tooltips

Conflicts:
	src/tools/zoom.coffee
Improve tooltip logic

- Once a tooltip is visible, quickly moving
  the cursor to another tool button should
  immediately hide the current tooltip and
  show the new one, with no delay. This improves
  ui scannability.

- When a tooltip is visible and the button
  is clicked, the tooltip should hide.

- If a tooltip is waiting to show and the button
  is clicked, the tooltip should not show.

These seem like small details, but they add up.
Make tooltips match the color of the button
Update appcache revision
Hide tooltip if visible
Longer delay
Refactor tooltip logic into new file
Update cache revision