Closes #61, clean up 'bench' and 'obs' data.
Closes #60, record per-query times.
Closes #62, record number of nodes.

Recorded in 'cluster.node_count'; this will help when dealing with
de-normalized csv data down the line.
Set default output format for 'show' to 'csv'.

Can't find a way to squeeze all the needed data into table output that
would fit on monitor without wrapping.