[ins] vf_extended: rename update_alt to update_z

this makes more sense as it is with z-down and vff_update_z_conf can be used for both vf_float and vf_extended_float
[ins] no baro update if vf_reset && !baro_initialized
[ins] gps_passthrough type for rotorcrafts
[rotorcraft] simple HITL by using ref as gps
[rotorcraft] gps_sim_hitl: set gps alt and hmsl

now the simple HITL should work with ins gps_passthrough
[modules] cam_roll: CAM_ROLL_START_MODE and remove cam_roll_switch
[chibios] make ringBuffer compile
[modules] meteo_france_DAQ: only print info message once
[modules] sonar_adc: add distance to struct
[ins] trying to fix ins xsens700
[tools] gen_modules_doc: update wiki url
[dox][mcu_periph] document some more stuff
update excludes in Doxyfile

and prevent copied chibios file to add doxygen groups
[airborne] remove unused agl and alt_vfilter

alt_vfilter is basically the same as ins/vf_float
[server] add airspeed data in FLIGHT_PARAM message
[server] send negative value if no airspeed available

on a second thought it is safer to tell that there is no airspeed data,
ground speed is already available in the message anyway
[server] change again airspeed field position

for compatibility with PPRZonDroid beta version
[rotorcraft] rc setpoint handling refactored

closes #684 which partially solves #599
[mission] add support for global coordinates in mission module
[ext] update libopencm3