Adjustment to GetParameterValueByName

<h4>Summary</h4>

Currently SetParameterByName is expecting an element while GetParameterValueByName is returning an element id. This submission makes the change to GetParameterValueByName so that it will return an element if the parameter storage type is ElementId.

A test case is added to check that SetParameterByName and GetParameterValueByName will work with the new change.

The original pull request for this one is:
https://github.com/DynamoDS/Dynamo/pull/3348

@pboyer 
PTAL