MB-6450: implemented new document editing API

Right now it's just wrapper for old capi calls API

Change-Id: Ib6b5d8b8b9f6ae76d66d7579b8a9c18a3c6fecca
Reviewed-on: http://review.couchbase.org/21221
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>