Fix SnapshotWritable SPartitioner to always be positive
Rename was not sorting by entity
Don't group by entity
Fix sorting to process featureId and date first
Partition renames by featureId + date
Added Mutator for mutating facts
Add featureId grouping to SnapshotWritable
FeatureReduction and Squash
Add squash to pivot
Support virtual features in pivot output
fixup! FeatureReduction and Squash
fixup! FeatureReduction and Squash

- Partition by featureId (still)
fixup! FeatureReduction and Squash

- Pass tombstone values to reductions