Changes to SDL control backend:
PC joystick code almost entirely rewritten. This should fix most of the problems OpenBOR has historically had with joystick support.
The engine now shuts down properly instead of exiting immediately when closed with F10, Alt+F4, or the window's "X" button.
Authored by: plombo 2010-08-05
Parent: [r2862]
Child: [r2864]
