Copter: check target of set-mode request from GCS

Issue discovered and fix contributed by Deadolous
AP_NavEKF: Track baro alt when pre-armed

This will help prevent spurious alt disparity warning messages for copter
AC_PosControl: bug fix dt calculation

fixes issue in which now could be earlier than _last_update_xy_ms
leading to a large dt value and a sudden lean on takeoff
AHRS_DCM: sanity check AHRS_RP_P and AHRS_YAW_P
AC_WPNav: bug fix sanity check of set_speed_xy

This corrects a bug that allowed the waypoint speed to be set to zero
Copter: print frame type in log headers
Copter: landing detector checks baro climb rate

Barometer climb rate must be -150cm/s ~ +150cm/s
This threshold is generous because we already use the inertial
navigation climb rate so this is just to catch cases where inertial nav
is very incorrect in it's climbrate estimates
DataFlash: log baro climbrate
Copter: completely disable vel controller
Copter: remove DO_MOUNT_CONFIGURE support

The functions in the mount lib didn't work anyway
Mount: remove CMD_DO_MOUNT_CONFIGURE support
Copter: remove debug
Copter: shorten ESC calibration message
Relay: reduce num relays to 2
RangeFinder: reduce num instances to 1
Copter: ReleaseNotes for AC3.2-rc13
Copter: version to AC3.2-rc13
AP_RangeFinder: auto-update PX4 ll40ls max/min distance

this allows the range of the Lidar to be set by the user using
RNGFND_MAX_CM and RNGFND_MIN_CM
RangeFinder: PulsedLight I2C addr to 0x62
Copter: fix to dcm-check to be continuous

dcm-check was triggering after 10 bad headings but these did not need to
be continuous meaning if the vehicle was flown long enough it would
almost certainly trigger a dcm-check failure and land