add timestamp field to uORB msgs; sync timestamp whenever possible

msg/actuator_armed.msg

+uint64 timestamp	# time since system start (microseconds)
 
 uint32 armed_time_ms	# Arming timestamp
 bool armed		# Set to true if system is armed

msg/actuator_controls.msg

+uint64 timestamp			# time since system start (microseconds)
 uint8 NUM_ACTUATOR_CONTROLS = 8
 uint8 NUM_ACTUATOR_CONTROL_GROUPS = 4
 uint8 INDEX_ROLL = 0
@@ -15,4 +16,3 @@ float32[8] control
 
 # TOPICS actuator_controls actuator_controls_0 actuator_controls_1 actuator_controls_2 actuator_controls_3
 # TOPICS actuator_controls_virtual_fw actuator_controls_virtual_mc
-

msg/actuator_direct.msg

+uint64 timestamp			# time since system start (microseconds)
 uint8 NUM_ACTUATORS_DIRECT = 16
 uint32 nvalues				# number of valid values
 float32[16] values			# actuator values, from -1 to 1

msg/actuator_outputs.msg

+uint64 timestamp		# time since system start (microseconds)
 uint8 NUM_ACTUATOR_OUTPUTS		= 16
 uint8 NUM_ACTUATOR_OUTPUT_GROUPS	= 4	# for sanity checking
 uint32 noutputs				# valid outputs

msg/adc_report.msg

+uint64 timestamp		# time since system start (microseconds)
 int16[12] channel_id		# ADC channel IDs, negative for non-existent
 float32[12] channel_value	# ADC channel value in volt, valid if channel ID is positive

msg/airspeed.msg

+uint64 timestamp		# time since system start (microseconds)
 
 float32 indicated_airspeed_m_s		# indicated airspeed in m/s
 

msg/att_pos_mocap.msg

+uint64 timestamp		# time since system start (microseconds)
 uint32 id			# ID of the estimator, commonly the component ID of the incoming message
 
 uint64 timestamp_received	# timestamp when the estimate was received

msg/battery_status.msg

+uint64 timestamp		# time since system start (microseconds)
 float32 voltage_v		# Battery voltage in volts, 0 if unknown
 float32 voltage_filtered_v	# Battery voltage in volts, filtered, 0 if unknown
 float32 current_a		# Battery current in amperes, -1 if unknown

msg/camera_capture.msg

+uint64 timestamp		# time since system start (microseconds)
 uint64 timestamp_utc		# Capture time in UTC / GPS time
 uint32 seq					# Image sequence number
 float64 lat					# Latitude in degrees (WGS84)

msg/camera_trigger.msg

+uint64 timestamp	# time since system start (microseconds)
 uint64 timestamp_utc # UTC timestamp
 
 uint32 seq		# Image sequence number

msg/collision_report.msg

+uint64 timestamp		# time since system start (microseconds)
 uint8 src
 uint32 id
 uint8 action

msg/commander_state.msg

 # Main state, i.e. what user wants. Controlled by RC or from ground station via telemetry link.
+uint64 timestamp			# time since system start (microseconds)
+
 uint8 MAIN_STATE_MANUAL = 0
 uint8 MAIN_STATE_ALTCTL = 1
 uint8 MAIN_STATE_POSCTL = 2
@@ -15,5 +17,4 @@ uint8 MAIN_STATE_AUTO_FOLLOW_TARGET = 12
 uint8 MAIN_STATE_AUTO_PRECLAND = 13
 uint8 MAIN_STATE_MAX = 14
 
-
 uint8 main_state		    	# main state machine

msg/cpuload.msg

+uint64 timestamp		# time since system start (microseconds)
 float32 load                    # processor load from 0 to 1
 float32 ram_usage		# RAM usage from 0 to 1

msg/debug_key_value.msg

-uint32 timestamp_ms		# in milliseconds since system start
+uint64 timestamp		# time since system start (microseconds)
 char[10] key			# max. 10 characters as key / name
 float32 value			# the value to send as debug output

msg/debug_value.msg

-uint32 timestamp_ms     # in milliseconds since system start
+uint64 timestamp	# time since system start (microseconds)
 int8 ind                # index of debug variable
 float32 value           # the value to send as debug output

msg/debug_vect.msg

-uint64 timestamp_us     # in microseconds since system start
+uint64 timestamp	# time since system start (microseconds)
 char[10] name           # max. 10 characters as key / name
 float32 x               # x value
 float32 y               # y value

msg/differential_pressure.msg

+uint64 timestamp				# time since system start (microseconds)
 uint64 error_count				# Number of errors detected by driver
 float32 differential_pressure_raw_pa		# Raw differential pressure reading (may be negative)
 float32 differential_pressure_filtered_pa	# Low pass filtered differential pressure reading

msg/distance_sensor.msg

 # DISTANCE_SENSOR message data
 
+uint64 timestamp		# time since system start (microseconds)
 
 float32 min_distance		# Minimum distance the sensor can measure (in m)
 float32 max_distance		# Maximum distance the sensor can measure (in m)

msg/ekf2_innovations.msg

+uint64 timestamp		# time since system start (microseconds)
 float32[6] vel_pos_innov  # velocity and position innovations
 float32[3] mag_innov 	# earth magnetic field innovations
 float32 heading_innov 	# heading innovation

msg/ekf2_timestamps.msg

 # this message contains the (relative) timestamps of the sensor inputs used by
 # ekf2. It can be used for reproducible replay.
 
-# the timestamp field (auto-generated) is the ekf2 reference time and matches
-# the timestamp of the sensor_combined topic.
+# the timestamp field is the ekf2 reference time and matches the timestamp of
+# the sensor_combined topic.
 
+uint64 timestamp		# time since system start (microseconds)
 
 int16 RELATIVE_TIMESTAMP_INVALID = 32767 # (0x7fff) If one of the relative timestamps
                                          # is set to this value, it means the associated sensor values did not update
@@ -22,4 +23,3 @@ int16 vision_attitude_timestamp_rel
 int16 vision_position_timestamp_rel
 
 # Note: this is a high-rate logged topic, so it needs to be as small as possible
-