artdaq

The automatic pause-and-resume functionality of AggregatorCore requires a full stop of DAQ data-taking, and in extreme cases can cause data loss. This should be replaced with a "rollover subrun" command which does not disrupt the DAQ, but simply updates the subrun number in EventStore, doing what is necessary to ensure the change is propagated to art.

This command will probably have to by synchronized somehow so that a subrun begins at a specified sequence ID for all components of the system.