Rename set, add, delete for 2.0 API

Change-Id: I106e19a26b91fe2f25b7036e33f79f5e5884c037
Reviewed-on: http://review.couchbase.org/41311
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Volker Mische <volker.mische@gmail.com>