The antenna tracker's system id (aka SYSID) should be different from
other vehicles but it's component id should be "1" like copter, plane
and rover.

this should not be needed any more

this replaces the special purpose routing in the AntennaTracker

Largely removes the sudden jerk that occurs when the user pushes the
safety switch

No functional change.
Flow runs from top to bottom with functions at top of file calling those
lower down.

Also set servo_limit flags for pitch

These capture the yaw and pitch range of movement in degrees

No functional change

No functional change

This ensure the tracker does not move in any mode until after the
startup delay has passed

No functional change

no functional impact

previously heartbeat messages from the vehicle could be processed twice.
Once at the top of hte handleMessage function where they were forwarded
onto the GCS and then again lower down in the function where all
received heartbeats were sent to the vehicle.