Copter: do_yaw takes yaw target from AttControl
Copter: add get_angle_targets_for_reporting

This returns the current earth frame roll, pitch and yaw targets which
can depend upon the flight mode
Copter: integrate get_angle_target_for_reporting

Used for logging and sending to GCS
Copter: remove control_roll, pitch, yaw from control files
Copter: remove control_roll, pitch, yaw variables