Listing collections may return incomplete data

A particular deployment might limit the number of entries listing a
collection may return.  In such a sitation, the API will still return
a 200 status code, but set the 'truncated' attribute in the collection to
indicated that not all the entries could be provided.

Partially implements bp list-limiting

Change-Id: I7352faa7ff345e5768cdd84ff0d6ca3530bffb48