Geofence upgrades

[KKalem]

• Geofence start action can now accept islands as well.
  • "inside" == "inside of any fence AND outside of all islands"
  • new reason for "outside" added to message: "INSIDE_ISLAND"
• Geofence start action can now be started many times
  • Each start will add to the list of fences or islands
• Geofence stop action can be used to reset islands or fences
• The node now
  • publishes the fences and islands as polygons, in vehicle/map frame
  • requires a "map_frame" parameter. This needs to a TF connected to the utm frame (utm_Z_B) of the vehicle's latlon
  • publishes rviz markers

Not very heavily tested. Seems to be working. Bugfixes welcome.