[flight_plan] set primitive should not delay next stage

when a set is called, it should not stop the navigation for 1/4 second.
[flight_plan] fix return primitive
[tools] parse IndexOfBlock inside procedures

a procedure can only see its own blocks
[fixedwing] if USE_BARO_BOARD: separate baro timer

before baro_periodic was running at PERIODIC_FREQUENCY in sensors_task,
which is too fast for ms5611 if periodic freq is > 100Hz
[ocaml][flightplan] No lexer when variable does not contain ocml functions

close #825
[imu] remove imu_float_init
[imu] correct body_to_imu naming and also set for ImuFloat
[fixedwing] fix typo
[stm32][spektrum] make it possible to redifine channels from airframe file
[rotorcraft] auto-enable UNLOCKED_HOME_MODE if HOME mode is used on RC

If you set MODE_AUTO1 or MODE_AUTO2 of the RC mode switch to AP_MODE_HOME
you can't get out of HOME mode again via RC by default, only via GCS.
So if you really want to be able to switch to HOME mode via RC,
enable UNLOCKED_HOME_MODE by default.

See also #823