MB-100: added another rebalance visualization

Change-Id: I0d5d353d8332d3ff8643b0e757b340e8450af47f
Reviewed-on: http://review.couchbase.org/25746
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-100: fixed drop of rebalance-out nodes in visualize-rebalance

Change-Id: Id7183ae3bfa3a728ceed279fca5603ea875901a9
Reviewed-on: http://review.couchbase.org/25747
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-8066: expose second checkpoint waiting in master events

I.e. so that we can analyze rebalance better

Change-Id: I61bfcca04463db3931192608f230d5d5c9bc1810
Reviewed-on: http://review.couchbase.org/25748
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>