update to control flow configuration classes
- allow use of a control flow expression in the configuration where an algorithm is expected (e.g. in ApplicationMgr.TopAlg), see 8bd37888
- fix issue with invalid properties of algorithms not being reported as errors, see 4b270396
- added a facade class to allow the implementation of fake algorithm configurables wrapping control flow graphs
- example implementation of a SuperAlgorithm with graph shape depending on a property