CBQE-0: move tuq_generator to common library for couchbase

Change-Id: I43de74f262cac5debe5a2d5dba990f67306aef85
Reviewed-on: http://review.couchbase.org/43804
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>