Allow large features to span multiple reducers on ingest
Ensure namespaceSizes ignores hidden files
Merge pull request #356 from ambiata/topic/ingest-feature-reducer-increase

Allow large features to span multiple reducers on ingest
Add days since reducer for Date style facts
Cherry pick ValueOrTombstone from Charles' PR
Use ReductionFold instead of Reduction
Interval reducers
Remove duplication in IntervalReducers
Add Interval expressions to expression Arbitraries

Update specs