Issue #31: Zoom on all diagram

src/main/java/ui/ScalableTGComponent.java

src/main/java/ui/TGCScalableWithInternalComponent.java

src/main/java/ui/TGCScalableWithoutInternalComponent.java

src/main/java/ui/TGCWithInternalComponent.java

src/main/java/ui/TGCWithoutInternalComponent.java

src/main/java/ui/TGComponent.java

src/main/java/ui/TGConnector.java

src/main/java/ui/TGScalableComponent.java

src/main/java/ui/ZoomUtil.java

src/main/java/ui/ad/TADComponentWithSubcomponents.java

src/main/java/ui/ad/TADOneLineText.java

src/main/java/ui/ad/TActivityDiagramToolBar.java

src/main/java/ui/atd/ATDAttackConnector.java

src/main/java/ui/atd/ATDCompositionConnector.java

src/main/java/ui/atd/ATDCountermeasureConnector.java

src/main/java/ui/avatarbd/AvatarBDCompositionConnector.java

src/main/java/ui/avatarbd/AvatarBDPortConnector.java

src/main/java/ui/avatarcd/AvatarCDCompositionConnector.java

src/main/java/ui/avatardd/ADDDiagramToolBar.java

.../ui/avatarmad/AvatarMADBelongsToCompositionConnector.java