[MSC2-25] Eliminating rollback phase
[MSC2-26] Eliminating good-for-nothing Parent -> Child task relationship
[MSC2-26] Refactoring - eliminated NEW and TERMINATED TaskController states
[MSC2-25][MSC2-26] Eliminating useless taskFactory parameter. Now that rollback phase is gone there's no reason to keep it. Also removing useless Parent -> Child tests.