preferred event not changed unless new event FAR is lower than OPA threhold or preferred event FAR greater than OPA threshold
Following S190421ar, there is a corner case where a candidate from a pipeline can have a high SNR along with a FAR > OPA threshold to incorrectly become the preferred event.
This merge request refactors the condition for making an event public into the
superevents module. The selection of preferred event now follows:
- Publishing criterion as the foremost condition
- Then CBC precedes over Burst
- Finally the SNR/FAR for CBC/Burst will break a tie