Correct lua joypad handler function names.  Fix #519
Prevent repetitive joypad axis states. Fix #521
Also create deadspace in negative joypad axis movement. fix #521
Move prevention of repetitive joypad movements to InputEvent. Fix #521
Return an event for all events. Fix #521
Merge pull request #520 from xethm55/master

Correct joypad handler functions and prevent repetitive joypad axis events