Bug 984253 part.1 Rename nsJSEventListener.(cpp|h) to JSEventHandler.(cpp|h) r=smaug

--HG--
rename : dom/events/nsJSEventListener.cpp => dom/events/JSEventHandler.cpp
rename : dom/events/nsJSEventListener.h => dom/events/JSEventHandler.h
Bug 984253 part.2 Merge nsIJSEventListener and nsJSEventListener r=smaug, sr=jst
Bug 984253 part.3 Rename nsEventHandler to mozilla::TypedEventHandler r=smaug
Bug 984253 part.4 Rename nsJSEventListener to mozilla::JSEventHandler r=smaug