ISSUE-72: The object of a membership triple isn't always the address of the created informational resource

Resolution: Close Issue-72, add ldp:membershipObject to allow overriding the object of the membership triple that gets added when the container creates a new member. LDP constrains the behavior only in the case where the input document contains 0:1 triples whose predicate p is the ldp:membershipObject 's object.
See https://www.w3.org/2013/meeting/ldp/2013-06-19#resolution_9

Here are the notes/examples from the piratepad relavent to this topic: http://piratepad.net/ge4VKecQWa

Let's say this LDPC has a membershipSubject of </people/roger> and membershipPredicate of pets:has_pet. If I POST the following to the LDPC:

<> a animal:Cat;
foaf:name "Zaza".

... a new resource is created.
And there is a new membership triple of

</people/roger> pets:has_pet </people/roger/zaza#this>

If one wants to keep the two resources separated, I might POST the following

------
<> a ldp:Container;
ldp:membershipPredicate pets:has_pet;
ldp:membershipSubject </people/roger>;
ldp:membershipObject foaf:primaryTopic .
-------

------
<> a ldp:Container;
ldp:membershipPredicate pets:has_petdocument;
ldp:membershipSubject </people/roger>;
ldp:membershipObject owl:sameAs .
-------

problem issue:
-------------
/people/roger/zaza:

<> foaf:primaryTopic <#this> .
<#this> a animal:Cat;
foaf:name "Zaza".
----------------




another way:
---------------
<> foaf:primaryTopic <#this> .
<#this> a animal:Cat;
foaf:name "Zaza".
</people/roger> pets:has_pet <#this> .
-------

or just post
----------------
<#this> a animal:Cat;
foaf:name "Zaza".
----------------

</people/roger> pets:has_pet </people/roger/zaza>

----------------
</people/roger/zaza#this> a animal:Cat;
foaf:name "Zaza".
----------------

However, the new membership triple in this case is not quite right. It still is :

</people/roger> pets:has_pet </people/roger/zaza>

... but it should really be :

</people/roger> pets:has_pet </people/roger/zaza#this>

--------
<> a ldp:Container;
rdfs:member <pets> .
~~~~~~~~
~~~~~~~
<pets>
ldp:membershipPredicate foaf:primaryTopic;
ldp:membershipSubject </people/roger> .