Just works.
Format editor.js.
Split arguments of enventHandler to name(or key name) and point(of mouse).
Rename point to mousePoint.
Encapsulate observing mouse move.
Change notifications from the control to the tool to event-trigger instead of function-calls.
Merge pull request #22 from pubannotation/show_pallet_on_mouse_cursor

Show the pallet on the mouse cursor