* Add state sync support
* fix incorrect test tempdir
* proto: move and update Protobuf schemas
* proto: lint fixes
* comment tweaks
* don't use type aliasing
* don't call .Error() when logging errors
* use create terminology instead of take for snapshots
* reuse chunk hasher
* simplify key encoding code
* track chunk index in Manager
* add restoreDone message for Manager
* add a ready channel to Snapshotter.Restore()
* add comment on streaming IO API
* use sdkerrors for error handling
* fix incorrect error
* tweak changelog
* syntax fix
* update test code after merge
Erik Grinaker