Joystick Support

Problematic Points:
* ViewHat as Buttons don't work. This means you can't use the quickbuttons that are typically there
*  XBox Morrowind separates "Use" and "Cast". PC combines them. Not a major problem, probably an improvement
* Implementing SDL_GameController should be done at some point, it handles game controllers better then SDL_Joystick, allows for more verbose button names ("Start" as opposed to "Button 10").
* Removing/Adding controllers which the program is running is problematic. Not sure why, but it worked before I switched development computers, perhaps some sort of SDL update?
ComboBox reacts on mousepressed events, when it should react on mousereleased. This results in clicking down, the menu responding and retracting. When you release the system thinks you've clicked on the item behind it. Thus this eats up the mousereleased event and makes everything work. I didn't build from SVN, so for all I know this has already been fixed.