support for onRelease listener and preventing automatic key repeats

[makoConstruct]

changes

new features:

• events now have an onRelease listener
• events do not repeat when a key is held down[the event will not fire a second time without first being released]

rationale:

• features:
  • I need an onRelease listener
  • I need that onRelease listener for using key combinations for doing dragging operations and I'm pretty sure repeat fires is not expected or useful in the most user cases. Maybe there should be a config option or.. hum, maybe it should be a part of the dsl. Well we'll cross that bridge when someone cares.
• key:
  • optionality structure made it unreasonably difficult to mesh in the new variable, so I've just assumed onRelease is the 6th variable and removed mention of the optionality stuff from the readme because articulating the new situation would make an unnecessary mess in readers' minds.
• general:
  • bind and unbind methods now take an optional event name[defaults to keydown]