JCBC-565: Adapting README for GA changes.

Change-Id: Ie2045178c33663cdfe58e1ee1041be0e285fb696
Reviewed-on: http://review.couchbase.org/41500
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>