Update to latest libcouchbase (2.4.0)

Change-Id: Ic1b28cfe7d6eb050c6c37ac1be80c953823e490f
Reviewed-on: http://review.couchbase.org/40041
Reviewed-by: Jeffry Morris <jeffrymorris@gmail.com>
Tested-by: Brett Lawson <brett19@gmail.com>
Mass 2.0 Refactor

Change-Id: I13b9bdb8b5f4564ac277da87a98f9f63e36850ab
Reviewed-on: http://review.couchbase.org/39934
Reviewed-by: Jeffry Morris <jeffrymorris@gmail.com>
Tested-by: Brett Lawson <brett19@gmail.com>
Release 2.0.0-beta

Change-Id: Ic2193818026bfe9090f72f5cba212746ee010ca0
Reviewed-on: http://review.couchbase.org/40285
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Brett Lawson <brett19@gmail.com>