rename pflowSuperCluster -> parentSuperCluster, superClusterBoxRef -> superClusterPFECALRef
point conversion producers at new BC collections
do not lock clusters when they cannot be added to a refined SC
Add rechit fraction threshold for PFClusters
Move regression inside PFECALSuperClusterAlgo and add configurable SC Et cut for output collections (set to 4GeV currently)
remove sc et cut from electron seed producer in default sequence since this cut is now applied upstream