added filter masks to CHANGES.
changed the histogram plots to use "stacked" mode as default again. To disable, use `--no-stacked`. Fixes #141.
fixed a bug where 0ms durations (and other 0 values) are not plotted in mplotqueries. Fixes #144.
mongos start at the beginning of the port range now.

makes it easier to start a sharded cluster and connect straight to a mongos.
included mongos port range at beginning in CHANGES.
use absolute data paths to better identify the ps aux | grep mongo outputs. fixes #143.