Adds support of fixed distance binary sensors

Adds support of fixed distance binary sensors

Changes managing of corner cases to adhere the range sensor message definition:
values < range_min or > range_max should be discarded

See: http://docs.ros.org/api/sensor_msgs/html/msg/Range.html
I don't know how resource constrained we actually are, but I feel this would be a bit more efficient if we had a parameter to say whether it was a fixed distance ranger to avoid checking the min_range/max_range for every single message.