distance_sensor: removed range_finder.msg def; readded max number of sonars

msg/range_finder.msg

@@ -1,13 +0,0 @@
-int16 RANGE_FINDER_TYPE_LASER = 0
-
-# range finder report structure.  Reads from the device must be in multiples of this
-# structure.
-uint64 timestamp
-uint64 error_count
-uint16 type				# type, following RANGE_FINDER_TYPE enum 
-float32 distance			# in meters
-float32 minimum_distance			# minimum distance the sensor can measure
-float32 maximum_distance			# maximum distance the sensor can measure
-uint8 valid				# 1 == within sensor range, 0 = outside sensor range
-float32[12] distance_vector # in meters length should match MB12XX_MAX_RANGEFINDERS
-uint8 just_updated # number of the most recent measurement sensor