Fix up the auto-pilot

[MrMcZ]

Simple idea. Just make autopilot turn while in motion instead of coming to a complete stop, turning and thrusting again. (which can happen quite a few times in a singke system due to gravity) Also if you do this please add backwards auto-pilot. Not as a selected mode between backward or forward but automatic depending on what direction your ship is pointed in relation to where you chose to autopilot to. That way you wouldn't half to turn fully around to go in the direction you wanted.