Add view methods to TxAsyncconnection base

These are useful and applicable there too

Change-Id: I662796ccd559e8ff482c0161cadd038ffae1e737
Reviewed-on: http://review.couchbase.org/31188
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>