Bug 984271 part.1-1 Separate mouse wheel handling helper classes and methods from nsEventStateManager.cpp r=smaug

--HG--
rename : dom/events/nsEventStateManager.cpp => dom/events/WheelHandlingHelper.cpp
rename : dom/events/nsEventStateManager.cpp => dom/events/WheelHandlingHelper.h
Bug 984271 part.1-2 Rename nsScrollbarsForWheel to mozilla::ScrollbarsForWheel r=smaug
Bug 984271 part.1-3 Rename nsMouseWheelTransaction to mozilla::WheelTransaction r=smaug
Bug 984271 part.1-4 Clean up WheelHandlingHelper.cpp r=smaug
Bug 984271 part.2 Rename nsEventStateManager to mozilla::EventStateManager r=smaug

--HG--
rename : dom/events/nsEventStateManager.cpp => dom/events/EventStateManager.cpp
rename : dom/events/nsEventStateManager.h => dom/events/EventStateManager.h
Bug 984271 part.3 Move OverOutElementsWrapper into mozilla:: namespace r=smaug
Bug 984271 part.4 Move the all other stuff in EventStateManager.cpp into mozilla:: namespace r=smaug