Ambiguity between AssociatedPositioningSystem and PositioningSystemCoordinate

Both, AssociatedPositioningSystem as well as the indirectly included PositioningSystemCoordinate instances refer to a positioning system. This creates and ambiguity because it cannot be ensured that the AssociatedPositioningSystem refers to the same PositioningSystem as all PositioningSystemCoordinates that are included in the AssociatedPositioningSystem via the included IntrinsicCoordinate. In order to mitigate this the subclassing of PositioningSytemCoordinate should be changed. PositioningSystemCoordinates that are referenced from an AssociatedPositioningSystem should not reference a PositioningSystem themselves. In this scenario the relevan positioning system for the coordinate is defined by the AssociatedPositioningSystem. This way the name of the class "AssociatedPositioningSystem" makes much more sense. However then referencing a PositioningSystemCoordinate from a AreaLocation, LinearLocation or SpotLocation the positioning system needs to be specified for the PositioningSystemCoordinate.