CBIDXT-130 : projector rebalance simulation.

Change-Id: I569f175c675e9abb7c78a79dc03bb6c79b2a827f
Reviewed-on: http://review.couchbase.org/40610
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>