Juwang - round trip test with class hierarchy

RoudTripTest today test a complex object with a newly build configuration and serialized/deserialized configuration. But it doesn't leverage  deserailizaed class hierarchy when deserialize the configuration. 

In a real client 's scenario, we have serialized class hierarchy and Task configuration,  then we need to deserialize the configuration with the deserialized class hierarchy.  This scenario now is covered in the RoundTripTests. 

This is to resolve issue #200.
Please add documentation about what this test tests. Also, this seems related to another line of discussion we are having around Tang's treatment of child classes. If so, please remove this test from the current PR and file one for that issue separately.