Care Free mode
care_free_heading in stabilization.c
[rotorcraft] add CareFree mode to settings/gcs
[rotorcraft] care free mode

- still not implemented for stabilization_euler
- move read_rc_setpoint_* functions to c file
- add GUIDANCE_H_MODE_CARE_FREE mode
- add stabilization float_euler subsystem
- use normal stabilization subsystem in NPS instead of hardcoded euler
care free mode for euler
removed todo euler care free
improved care free euler
fixed misplaced brace
[rotorcraft] AHRS_EULER_INT message only for CMPL_EULER
Merge branch 'care_free_mode'

New "care free" mode that keeps the yaw ref pointing in initial direction:
AP_MODE_CARE_FREE_DIRECT: otherwise like the normal ATTITUDE_DIRECT mode.
CARE_FREE is implemented as a horizontal submode: GUIDANCE_H_MODE_CARE_FREE
so it could be combined with other vertical modes as well...

Other changes:
- move read_rc_setpoint_* functions to c file
- added missing modes to settings/telemetry
- add stabilization float_euler subsystem
- use normal stabilization subsystem in NPS instead of hardcoded euler

closes #390 and closes #391
suppress compilation warning for px4flow
[ahrs] remove ltp_to_imu_euler from int_cmpl_quat
Ubuntu application launcher for Paparazzi
OTF! typo, description
add recent Digi XBee pro modem (metal case) to udev rules
[tools] propsal to use meld instead of tkdiff, which is nowadays removed from ubuntu repo
Merge pull request #394 from RoboticaTUDelft/pprz_center_tool_update

meld instead of tkdiff in pprz center
[http] get the proxy settings from env
Merge remote-tracking branch 'paparazzi_main/master'