Add a link attribute to the CollectionSnapshot
 #25 : The changeset for a Collection is now numeric indexed based
Merge pull request #27 from Taluu/set-collection-keys

Set changesets of collections to be more collection like
Use PropertyPath instead of a wild guess for CollectionSnapshot
Merge pull request #29 from Taluu/property-path-collections

Use PropertyPath instead of a wild guess for CollectionSnapshot
Remove unused ArrayAccess in CollectionSnapshot