Copter: remove command_description.txt

Description in this file were out of date or incomplete and it is better
for people to refer to the MAVLink documentation or the
/libraries/GCS_MAVLink/message_definitions/common.xml and
ardupilotmega.xml files
AutoTest: add AVC_copter to location

The existing AVC location is for Rovers.  Planes and copters take-off
from a position slighly further north.
Copter: enable PARACHUTE and RALLY for all but APM
Copter: AC3.2-rc2 release notes and version
Copter: remove unused pos vector functions

removed pv_latlon_to_vector, pv_get_lat, pv_get_lon.
it would probably be best if these were moved into the Math library