CBQE-1531: added possibility to load data with flags

Change-Id: I04e29a8cbab655baf81a4a59c74132791b119ca8
Reviewed-on: http://review.couchbase.org/29620
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>