Persistent Change Domain

As the changes of updates #35 should be reversible, an editing domain is needed that records all changes. This domain also needs to provide the functionality to analyze the impact of changes (Change impact analysis). As the changes have to be analyzed not only on runtime, the changes made to the EMF model have to be stored in an file. This allows reversing the change of updates of #35, as they concern not only one domain object/diagram but multiple ones. This change directory hast to be persistent. The Plugin we want to use for this will probably be EMF Ecore.