Add 'connection pool' example

Change-Id: Ib777bee98318cd25fd63c4377bb2eb0f68fe2aab
Reviewed-on: http://review.couchbase.org/29117
Reviewed-by: Matt Ingenthron <matt@couchbase.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>