Add a 'persistent' flag to receive event, all persistent continuations that were in TS in BASE deploy are mergeable
Per , both consume and produce events need the persistent flag. Merging rules for both need to be changed. I believe you are going to need the testing infrastructure developed in Kents pr though.
A 'COMM.direction' flag is going to be needed in order for us to discern which side of the COMM-event was already in TS and which one is incoming (4! vs !4).
all merging rules involving C (except those involving P or !!) are implemented (in MultiParentCasperMergeSpec all related `conflictsForNow` are `merges`, all current `conflicts` are `conflicts`)