* Added a guard when removing waypoints to catch an error

* Added a guard when removing waypoints to catch an error
* Simplified the distance callbacks a bit so the outer distance makes more sense
* Moved the arrow rotation function out of the OnUpdate
* Use the arrow rotation function rather than the OnUpdate function to ensure things are displayd correctly on options change
* Make the distance list local to the point, instead of the callbacks table
* Release the callbacks table when the waypoint is cleared