syntax checking for fault trees and adding fault icon

modeling/AVATAR/faulttreetest.xml

modeling/SysMLSec/at_zeuszitmo.xml

src/main/java/faulttrees/Fault.java

src/main/java/faulttrees/FaultElement.java

src/main/java/faulttrees/FaultNode.java

src/main/java/faulttrees/FaultTree.java

src/main/java/ui/AttackTreePanel.java

src/main/java/ui/FaultTreePanel.java

src/main/java/ui/FaultTreePanelTranslator.java

src/main/java/ui/GTURTLEModeling.java

src/main/java/ui/MainGUI.java

src/main/java/ui/ModeManager.java

src/main/java/ui/TGUIAction.java

src/main/java/ui/atd/AttackTreeDiagramToolbar.java

...eractivesimulation/JFrameAvatarInteractiveSimulation.java

src/main/java/ui/ftd/FaultTreeDiagramToolbar.java

src/main/java/ui/util/IconManager.java

src/main/resources/ui/util/ftdfault.gif