added simulator
PID controller added
position_vector class added
vehicle_control class added
Precision_land.cnf: add camera index
sc_video: use camera index from config file
Git: ignore eclipse files
vehicle_control: reduce to just yaw and velocity control
PrecisionLand: add calls of vehicle_control
Merge remote-tracking branch 'upstream/randy2'

Add mavlink interface
Integrated simulator into SITL. Cleaned up repo