Merge remote-tracking branch 'upstream/master' into new_state_machine

Conflicts:
	src/examples/fixedwing_control/main.c
Minor state machine improvements and fixes for IO safety / in-air restart handling
Two hacks here to make it compile
Software version check fixes
multirotor_pos_control: position controller implemented
position_estimator_inav cosmetic changes
Merge branch 'sdlog2' into seatbelt_multirotor
Merge remote-tracking branch 'upstream/master' into new_state_machine
Fixed param save
Default parameters updated for position_estimator_inav and multirotor_pos_control
Merge branch 'master' of github.com:PX4/Firmware into fmuv2_bringup
Added l3gd20h detection
Merge pull request #6 from skelly/l3gd20h_support

Added l3gd20h detection
Introduced new actuator_safety topic
Arming with IO working now
Beep when mode is not possible
multirotor_pos_control fixes, introduced HARD control mode (disabled by default)
Merge commit 'b714c5c9d1d38132df5cf4bff9a1fd92163be550' into seatbelt_multirotor
Controllers should not access state machine anymore but access the vehicle_control_mode flags
Prevent flips at high throttle

Conflicts:
	src/drivers/ardrone_interface/ardrone_motor_control.c