MB-100 Collect scheduler stats for our processes.

Change-Id: I2a95ec27ea7c6f1ff2018ce6968d2fd58d2028d6
Reviewed-on: http://review.couchbase.org/27664
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>