Remove ConnHandlerDelete/Mutate and use the ConnHandler API's

This change moves the tap mutation and deletion API's to the
TapConsumer class. It also removes code that was used for 1.x
compatibility. This means that we now expect that all tap
messages contain a meta data section.

Change-Id: Ic693b9038c5fb94c87f7451c878a0a3c2e63f48c
Reviewed-on: http://review.couchbase.org/31796
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>