Bug in getHeading function
GPS - requires testing

GPS manages communications with the GPS device.  It also manages
waypoints, and the information required to reach one.
Inside GPS.c, at the top of the file, there are global variables that
control the UART communications.  These values will undoubtedly need
readjusting.  I was just guessing.
Merge pull request #1 from jcronq/GPS-TEST

Gps test