Better support for traditional joysticks.

Some changes to make things work better with real joysticks.

The throttle lever on my joystick was way too sensitive because it was only using half the range. I added an option to the input config files to control how the thrust axis is handled. For gamepads it does the same as before (using only the + half of the axis) because they are spring loaded. But for joysticks with a dedicated throttle lever it makes more sense to use the full axis. Also, since it doesn't return to center, adjusting ASL is disabled in this mode.

I also added support for using the hat switch to control pitch and roll trim.