General: Cancun Stop

Calling cancun.sh stop will kill all cancun processes
Merge branch 'master' into experimental
Modules: Aprs Touch Tone Random Position

Once we decode suffix callsign taken from:
 http://www.retroscape.com/aprstt/
assign a random position within your city.

Lot of work to be do to determine our city specially
in cases where repeaters covers more than 2 cities.