Added ObjectFlows, ControlFlows etc as seen in activityWithCreateObjectAction/model.uml

Added ObjectFlows, ControlFlows, InitialNode, Parameter,
ActivityParameterNode, added also names to the flows.
Extended EventHelper functionality

to work with both ActivityNodeEntryEvent and ActivityNodeExitEvent;
added method to obtain the event's CreateObjectAction; added method to
obtain the event's CallOperationAction
Created ActionHelper to provide helper methods for CreateObjectAction and CallOperationAction
Added the handling of external CallOperationAction entry events [work in progress]

new: adding the created fUML Object_ to CreateObjectAction's OutputPin;
adding the created fUML Object_ to CallOperationAction's InputPin;
calling callOperation on the CallOperationAction event [work in
progress]