Add Lat/Lon to GPS and new compass sensor

Hello, I think to be more realistic the GPS sensor should return lat/lon/alt values. These changes add those values (x,y,z are still there as well). There is heading and speed to be like NMEA 0183 GPRMC message. Also a very simple compass sensor is added. What do you think?

Background: I've been playing with MORSE trying to simulate a little GPS guided car with a Hokuyo stuck to the front for obstacle avoidance.

* This is my first try at a pull request on GitHub so preemptively sorry for everything.

Zach