commander: Added time of RC-loss/gain to the mavlink_log_critical message to better inform the user
commander: Added duration of rc-loss to mavlink_log_critical message
Enable IO safety parameter
Don't go into an error state if we are temporarily powering via USB on the bench
Merge pull request #1416 from sjwilks/calibrate_usb

Don't go into an error state if we are temporarily powering via USB on the bench
Simplify error messages for NSH term
NSH term: Only time out if no arming information is available, if arming information is available abort if unconnected on arming
Encode RC type in RSSI field for GCS
Force RSSI to zero if RC is lost
Configure led ring and enable heartbeat on it
Merge pull request #1421 from PX4/ledring

Configure led ring and enable heartbeat on it
Build fix
Ensure MAVLink app has enough stack space
Remove huge memory overhead in RC channels topic, was completely unnecessary
Encoder logging support.
Shortened encoder logging names.
Update NuttX, print stack trace on stack overflow handler
Merge branch 'master' of github.com:PX4/Firmware
Commander: Improve calibration routines to produce more conscise and better sequenced instructions
Time out on serial instead of just hanging there