Bug 731746 part 1.  Add a constructor on nsDOMEventTargetHelper that takes a window, for use by JS-implemented event targets.  r=smaug
Bug 731746 part 2.  Change JS-implemented webidl codegen to pass an nsPIDOMWindow, not an nsISupports, to the object constructor.  r=mccr8
Bug 731746 part 3.  Change JS-implemented webidl codegen to always invoke the parent constructor if there is a parent interface.  r=mccr8
Bug 731746 part 4.  When wrapping a JS-implemented webidl object, define the new object as a property on the implementing object.  r=mccr8