Workflow.py: in showAsXML, iff show variable's expression as getId when variable is action, and it has default_expr.

WorkflowTool.py: add variable's expression as getReference iff when variable is action and it has a default_expr.

WorkflowTool.py: Enhance doActionFor compatibility at the case which both workflow are assigned to the same object type AND workflow has a prior initial letter to DC workflow.

Document/InteractionWorkflow.py: remove worklist showAsXML, because interaction workflow donesn't have worklist.