JCBC-557: Improvide documentation in the .document package.

Change-Id: If32da68c2210b2d86edaef631e68310fb8f85568
Reviewed-on: http://review.couchbase.org/41484
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>