Don't crash when the response does not contain a valid resource ID.
etag support.
Merge remote-tracking branch 'origin/bugs/nil_resource_id'
Merge remote-tracking branch 'origin/features/etags'
Merge remote-tracking branch 'upstream/master'
Pass relationship info along when looking for representations of entities.
delete object from backingcontext if 404
[Issue #225] Revert commit "[Issue #109]
resolving merge conflicts, when saved object did changed
nil resource id
Merge commit '06c1f22fbceda44f575b3cf37f865a33b2528d42'

Conflicts:
	AFIncrementalStore/AFIncrementalStore.m
Initial work migrating to AFNetworking 2.2.1
More work integrating with AFNetworking 2.2.1
Revert: 06c1f22fbceda44f575b3cf37f865a33b2528d42
Successfully migrated to AFNetworking 2.2.1