Upgrade poacher, saws and notion to remove test dependencies from jar
Add min and max reducers, composable interval expressions.
Merge pull request #382 from ambiata/topic/less-dumb-interval

Composable interval and min/max reducers
Chord and Snapshot mappers should drop facts not in dictionary.

Fixes #381.

This change also introduces a set of dropped counters for
visibility into what is being dropped for debugging purposes,
_however_ given that this is a fairly standard situation in
the future we should consider moving it behind a debug flag
or similar to avoid polluting debugging with noise.