add support for windows stats collection and enable beam rss test for windows

Change-Id: Iae449c23dbeaa5361c477e6e7a8c7d83b4135d55
Reviewed-on: http://review.couchbase.org/42634
Reviewed-by: thomas anderson <thomas.couchbase@gmail.com>
Tested-by: thomas anderson <thomas.couchbase@gmail.com>