Make WindowEvent implement the Event interface
Fill out MouseButtonEvent
Add MouseMotionEvent and move MouseButton into mouse.go
Add mouse motion and button events to convertEvent
Add mouse wheel event
Add joystick events
Start keysym support
Add TextEditingEvent and TextInputEvent
Merge remote-tracking branch 'nasuada/moarevents' into moarevents
Extract keyboard events to separate package
Add key code constants
Add scancodes and string conversion
Move Scancode into separate file
Fold KeySym into event.go
Switch to plain-old-struct event API
Update showimage demo to use new events API
Add controller and user-defined events
Finish last events
Add EventType.String method
gofmt