Added draft upstream barrier
Cleaning seep-common and seep-worker
Further codebase cleaning...
Sketching file source at API level
Finished design of DataOrigin API on seep-common. Added support for file sources.
More advances on file adapter and file selector. checkpointing...
Basic implementation of file source
Debugged file declaration stage and added some additional unit tests
Added task to copy seep system files to a deploy directory to ease this job
Merge remote-tracking branch 'upstream/ra-dev' into ra-dev