* Refactor mergeSetIncrease to return the current BFS block to allow easier merging
* Remove unneeded Heap/HashSet usages
* Add new IsAnyAncestorOf to DagTopolyManager
* Check if the new candidate is in the future of any existing candidate
* Add comments and fix off-by-one in the mergeSetIncrease queue
* Fixed DAGToplogy test mock
* Fix review comments