TEZ-1667. Add a system test for InitializerEvents. (sseth)
TEZ-1668. InputInitializers should be able to register for Vertex state
updates in the constructor. (sseth)
TEZ-1656. Grouping of splits should maintain the original ordering of splits within a group (bikas)
TEZ-1396. Grouping should generate consistent groups when given the same set of splits (bikas)