Update on MSC loader

src/sddescription/MSC.java

src/sddescription/SDExchange.java

src/ui/MSCDrawer.java

src/ui/TDiagramPanel.java

src/ui/TGUIAction.java

...ui/interactivesimulation/JFrameInteractiveSimulation.java

src/ui/sd/SequenceDiagramPanel.java