Handling of keyboard events : Key Up.
\param key : unicode code of key
\param keyCode : virtual keycode for non ascii keys - see \ref VirtualKeyCodes in keycodes.h
\param modifiers : any combination of KeyModifier - see \ref KeyModifier in keycodes.h
\return kResultTrue if the key is handled, otherwise return kResultFalse.
Handling of keyboard events : Key Up. \param key : unicode code of key \param keyCode : virtual keycode for non ascii keys - see \ref VirtualKeyCodes in keycodes.h \param modifiers : any combination of KeyModifier - see \ref KeyModifier in keycodes.h \return kResultTrue if the key is handled, otherwise return kResultFalse.