Always snapshot the last fact before a window
Merge pull request #365 from ambiata/topic/snapshot-window-last-fact

Always snapshot the last fact before a window
First cut at initial feature fn requirements
Proportion functions.
Ammend sum_by
Merge pull request #263 from ambiata/topic/feature-functions

First cut at initial feature fn requirements
Bump Mundane to inlude _DirPath exclusion
Bump notion, saws, poacher
Merge pull request #369 from ambiata/topic/bumping-mundane

Bump Mundane to include _DirPath exclusion, also bump poacher, notion and saws with updated Mundane.
Added snapshot with V0 to data-regression
Added another ingest with V0