create temperature_compensation module

- this is a new module for temperature compensation that consolidates the functionality previously handled in the sensors module (calculating runtime thermal corrections) and the events module (online thermal calibration)
 - by collecting this functionality into a single module we can optionally disable it on systems where it's not used and save some flash (if disabled at build time) or memory (disabled at run time)

ROMFS/px4fmu_common/init.d/rc.thermal_cal

@@ -5,12 +5,37 @@
 # NOTE: Script variables are declared/initialized/unset in the rcS script.
 #
 
-set TEMP_CALIB_ARGS ""
+set TEMP_COMP_START ""
+
+if param compare TC_A_ENABLE 1
+then
+	set TEMP_COMP_START "true"
+fi
+
+if param compare TC_B_ENABLE 1
+then
+	set TEMP_COMP_START "true"
+fi
+
+if param compare TC_G_ENABLE 1
+then
+	set TEMP_COMP_START "true"
+fi
+
+if [ "x$TEMP_COMP_START" != "x" ]
+then
+	temperature_compensation start
+fi
+
+unset TEMP_COMP_START
+
 
 #
 # Determine if a thermal calibration should be started.
 #
 
+set TEMP_CALIB_ARGS ""
+
 if param compare SYS_CAL_ACCEL 1
 then
 	set TEMP_CALIB_ARGS "${TEMP_CALIB_ARGS} -a"
@@ -34,7 +59,7 @@ fi
 #
 if [ "x$TEMP_CALIB_ARGS" != "x" ]
 then
-	send_event temperature_calibration ${TEMP_CALIB_ARGS}
+	temperature_compensation calibrate ${TEMP_CALIB_ARGS}
 fi
 
-unset TEMP_CALIB_ARGS
+unset TEMP_CALIB_ARGS