Implement steady-state replication, initial sync, master/slave propagation of UUIDs.
Lookup collections by UUID in applyOps
applyOps command should add collection UUIDs to each of its oplog entries
Replicate index builds as the createIndexes command instead of as inserts into system.indexes
Two Phase Drops: rolling back cross database renameCollections fails if there is both a dropTarget and dropSource collection
applyOps should work with a createIndexes command without a UUID