fix MPS-18743 MPS looses changes: reloading does not depend on whether model is loaded or not
fix MPS-18743 MPS looses changes: simplify code
fix MPS-18743 MPS looses changes: sourceTimestamp is set on construction
fix MPS-18743 MPS looses changes: remove unused method
fix MPS-18743 MPS looses changes: remove updateTimestamp () where it's not needed
fix MPS-18743 MPS looses changes: add updateTimestamp to reloadContents
fix MPS-18743 MPS looses changes: fix compilation in idea-plugin
SModelRepositoryListener: doc comment rewritten (reviewed by Simon)