tallyard v0.4.2

This release greatly speeds up the marshalling done during startup time by
storing zk proving+verifying keys in files separate from the main elections json
file.

The sync filter also now correctly includes state events in both rooms' state
lists _and_ their timelines.

David Florness (8):
      Actually use custom syncer and fix inheritance from DefaultSyncer
      Log reading and unmarshalling of elections file
      Control sync filter via the new custom syncer
      Correctly include state events in sync timeline
      Won't do TODO
      Speed up marshalling by storing keys in separate files
      Print helpful error message when the map schema is incompatible
      Bump version to v0.4.2