Increase overall gamepad sensitivity (again)

Also, the default has been increased from 16 to 32. It was suggested by
Average in the Doomworld forums to apply acceleration to gamepad
turning. This doesn't seem like a good idea. After checking the DOOM 3
BFG Edition source code, and playtesting the game at its lowest and
highest horizontal sensitivity settings, I feel these simple changes now
have the sensitivity how it should be.