Parallel execution of two algorithms within a workflow

[knoepfel]

DUNE US S&C R&D item 080

[knoepfel]

The implementation of Phlex v0.1.0 supports parallel execution of two algorithms within a workflow using oneTBB's flow graph. We do not, however, have a unit test that specifically checks for parallel execution of those algorithms.

This milestone should be revisited to determine whether it should be rephrased (e.g. "concurrency execution" vs. "parallel execution") or whether a test can be developed that truly checks for parallel execution.