Entry ID and Follow work

Made POSTed entries always have generated IDs. This includes storing
the original ID in a separate attribute.
Added date return to follow check so that correct date of follow
relationship can be used in PUTs. Also based the response code on
whether it was created or already existed.
Added paging to follower and following resources.
Fixed bug where start index wasn’t used in feed resource. Added tests
for start and count params for streams and feeds.