delete drv_airspeed.h (all IOCTLs), airspeed driver lib

- differential pressure now processed downstream like other sensor data (accel/gyro/mag/etc)
 - rename msg differential_pressure -> sensor_differential_pressure
 - add device id and timestamp_sample to all messages
 - calibration performend directly on raw data and SENS_DPRES_OFF parameter updated
 - remove Airspeed base class from existing differential pressure drivers
 - name differential pressure drivers consistently (no _airspeed suffix)

ROMFS/px4fmu_common/init.d/rc.sensors

@@ -126,21 +126,11 @@ then
 	then
 		if param compare CBRK_AIRSPD_CHK 0
 		then
-			sdp3x_airspeed start -X -q
-			sdp3x_airspeed start -X -a 0x22 -q
+			sdp3x start -X -q
+			sdp3x start -X -a 0x22 -q
 
-			# Pixhawk 2.1 has a MS5611 on I2C which gets wrongly
-			# detected as MS5525 because the chip manufacturer was so
-			# clever to assign the same I2C address and skip a WHO_AM_I
-			# register.
-			if [ $BOARD_FMUV3 = 21 ]
-			then
-				ms5525_airspeed start -X -b 2 -q
-			else
-				ms5525_airspeed start -X -q
-			fi
-
-			ms4525_airspeed start -X -q
+			ms4525 start -X -q
+			ms5525 start -X -q
 
 			ets_airspeed start -X -q
 		fi
@@ -150,5 +140,3 @@ fi
 ###############################################################################
 #                            End Optional drivers                             #
 ###############################################################################
-
-sensors start

ROMFS/px4fmu_common/init.d/rcS

@@ -322,11 +322,14 @@ else
 	# Sensors System (start before Commander so Preflight checks are properly run).
 	# Commander needs to be this early for in-air-restarts.
 	#
+	sensors start
+
 	if param greater SYS_HITL 0
 	then
 		set OUTPUT_MODE hil
-		sensors start -h
+
 		commander start -h
+
 		# disable GPS
 		param set GPS_1_CONFIG 0
 
@@ -371,7 +374,6 @@ else
 		set AUX_MODE pwm4
 	fi
 
-
 	# Check if ATS is enabled
 	if param compare FD_EXT_ATS_EN 1
 	then

ROMFS/px4fmu_test/init.d/rc.sensors

@@ -16,11 +16,11 @@ if board_adc start
 then
 fi
 
-if sdp3x_airspeed start -X
+if sdp3x start -X
 then
 fi
 
-if ms5525_airspeed start -X
+if ms5525 start -X
 then
 fi