Navigability & Association name direction

[MikeKing]

An association end has a number of properties, including multiplicity, role name and navigability.

The notation to represent navigability is an open arrow on the association end.

So the choice of true or false for the navigability should be on the association end (source or target in EA), and should not be a property of the association as a whole.

One should be able to select an end of the association and then set its multiplicity, role name and navigability.