Add pretty print ops/sec and population status

Change-Id: Ia21c7a90bac7dbb632f2644307a9f9ba59ea21b2
Reviewed-on: http://review.couchbase.org/42126
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>