px4io: split io_handle_battery() out from io_handle_status()

ready to add vservo and rssi
uORB: added new servorail_status object

used for VSERVO and RSSI on FMUv2
px4io: added monitoring of vservo and vrssi

publish via servorail_status ORB topic
added error_count field to sensor report structures
perf: added perf_event_count() method

this allows drivers to get an event_count from a perf counter
Merge branch 'master' of github.com:PX4/Firmware into status_monitoring
drivers: report error_count in drivers where possible
Merge branch 'master' of github.com:PX4/Firmware into status_monitoring
Merged status changes
State machine fixes for HIL
Robustified flight close to waypoints
px4io: make "too high rate" warning consistent with real behavor
Merge pull request #442 from PX4/px4io_rate_fix

px4io: make "too high rate" warning consistent with real behavor
multirotor_att_control: cleanup, some refactoring
px4io: major optimization and cleanup
px4io: code style fixed
commander: remove duplicate publishing of vehicle_control_mode and actuator_armed topics, remove unused "counter" field from topics
Added useful default gains
Fixed turn radius return value
Added support for dynamic turn radii