Re: Proposal to close ISSUE-59 (recursive-delete): Reconsider usage of Aggregate/Composite construct to get predictable container delete behavior - take #2

If we have two types of membership as in the proposal below and if the container is
deleted one type of member MUST be deleted and the other type of member MAY be deleted
then this is equivalent to members being either members which MUST get deleted or links
which get deleted but the resources they point to MAY or MAY NOT get deleted.

In such a model, resources that are included in a collection using links can belong to more than one
collection.  This solves the other issue we have re.  resources belonging to more than one collection.

> 3. specify that on deleting a container LDP servers MUST delete the container and member resources listed as contained via ldp:contains, and MAY delete other member resources (typically to satisfy internal requirements).
>
> So if I have:
>
> <> a ldp:Container;
>    rdfs:member <a>.
>
> and I create <b> using POST to the container, I end up with:
>
> <> a ldp:Container;
>    rdfs:member <a>, <b>;
>    ldp:contains <b>.
>
> When I delete the container, both the container and <b> get deleted. <a> MAY be deleted.