AC_Fence: add interface for retrieving exclusion polygons
AC_Fence: add interface to get exlusion polygons to polyfence loader
AC_Fence: add suport for inclusion circles
AC_Fence: add option for compiling-out FENCE_POINT protocol support
AC_Fence: get_exclusion_polygon and get_boundary_points set num_points to zero on failure
AC_Fence: use Debug(...) to hide debug messages
AC_PolyFence_loader: add methods to retrieve all inclusion zones
AC_PolyFence_loader: valid simply returns true if a polygon boundary can be returned
AC_Fence: add get_exclusion_circle
AC_Fence: add get_exclusion_circle_update_ms accessor
AC_Fence: PolyFence_loader gets inclusion circle accessors
AC_PolyFence_loader: add and use semaphore to protect loaded fence
AC_Fence: move fence breach check below fence type checks
This allows us to provide more information to the user about why they
are breached.
For example, if the radius is negative you are considered in breach of
it - but we'd tell you you were breached, not that your radius was
invalid
AC_Fence: clear the fence if we discover the user has set the fence count to zero
Peter Barker
714a3e2462