Piping prune function through the VersionedStore factory method
Ian comment
remove \n
Frozen keys
Compiling
Merge pull request #476 from twitter/dcl/prune

Piping prune function through the VersionedStore factory method
FrozenKey tests
Merge pull request #477 from twitter/feature/ianoc_frozen_keys

Feature/ianoc frozen keys
Make HDFSState public
Merge pull request #478 from twitter/jco/unhide_classes

Make HDFSState public