This makes us look like Rover and Plane in terms of namespacing for the
Mode classes, and removes a wart where we #include mode.h in the middle
of the Mode class.
This was done mechanically for the most part.
I've had to remove the convenience reference for ap as part of this.
bnsgeyer and rmackay9 contributed to these changes
make_safe_shut_down waits for spool down before disarming
remove use of attitude_control::set_throttle_out_unstabilized to consolidate logic between multicopters and tradhelis
add follow to FLTMODEx param descriptions
remove follow's set_velocity method
10hz logging of desired velocity in follow mode
follow mode uses pos error P gain
add send-debug-via-mavlink option
don't enter follow if follow lib is disabled
follow debug slowed to 1hz
disable follow on min-features builds
Randy Mackay
Peter Barker
Pierre Kancir
bnsgeyer
Leonard Hall
Dr.-Ing. Amilcar Do Carmo Lucas
Andrew Tridgell
Michael du Breuil