[Sirius][Integration] Umbrella bug for all Papyrus issues due to Sirius integration

Here we reference the issues due to the Sirius integration inside Papyrus. Often we find "bad" solution to the initial problem

#49 The editor is still dirty on the opening

• we propose to do undo after the opening of the editor

#40 [Sirius Integration] An imported model is re-written during save

• we iterate on the resource to do resource.setModified(false); (see MR !65 (diffs))

#24 (closed) The editor is dirty on the opening

I remember I called several modelSet.save() during the model creation/session creation.

We fix some issue , to be sure all files will be here, to avoid NPE, like here : org.eclipse.papyrus-model2doc#6

#52 [Sirius][Integration] Several commands are executed for each creation in a Sirius Diagram