AP_NavEKF: Track baro alt when pre-armed

This will help prevent spurious alt disparity warning messages for copter
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
HAL_AVR: fixed warning
Plane: disable CLI by default

it really isn't needed any more, and saves 20k of flash on APM2
Plane: display min as well as max loop delta_t
AP_L1_Control: fixed some warnings
AP_TECS: fixed some warnings
AP_Terrain: fixed a warning
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: remove debug
Copter: ReleaseNotes for AC3.2-rc13
Frame_params: 3DR_Iris+.param
Add GPS_HDOP_GOOD
AP_InertialSensor: first steps in frontend/backend split

This converts the MPU6000 driver to a frontend/backend structure, and
disables all other drivers. They will be progressively re-enabled as
each is converted
AP_InertialSensor: converted HIL backend, which gets SITL working
SITL: update for new AP_InertialSensor API
AP_InertialSensor: converted PX4 driver to new API
AP_InertialSensor: converted the MPU9250 driver to new API
AP_InertialSensor: converted the APM1/Oilpan driver to new API