Added case StatementRef for conversion from jObject to StatementBase
Added case SubStatement for conversion from jObject to StatementBase, checking for nested SubStatements
Adjust SubStatement object handling in Statement/StatementBase

* Add unit test for detecting non-null SubStatement as Statement object
Create Support class for creating shareable objects for test cases
Start SubStatement testing with nested test
Merge pull request #9 from brianjmiller/master

SubStatement as 'object' in Statement handling