Joystick Support

To be clear "Joystick" also refers to Game Controllers. No idea why anyone would want to play morrowind with a traditional joystick.

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?
* No mouseless interfaces, you can just use a stick as a mouse. Don't work too badly, either.
* I don't know if MyGUI uses keypresses anywhere, but all button presses are currently sent to MyGUI as Esc to easily skip the intro videos. I played the game for a bit and encountered no issues with this
You can retrieve the current value of a channel directly, so it is unnecessary to assign this value in the channelChanged event. The member variables serve no purpose.