Bug 139986 [CommonNavigator] Convert catch(Error/Throwable) to SafeRunner
In several places the CN framework uses catch(Error/Throwable) to ensure that code does not bring the framework down. Change these to use SafeRunner.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonNavigator.java
* 
	 * <p>
	 * Note: This method is for internal use only. Clients should not call this
	 * method.
	 * </p>
	 * 
	 * @see org.eclipse.ui.part.ViewPart#saveState(org.eclipse.ui.IMemento)
	 */
	public void saveState(IMemento aMemento) {
		aMemento.putInteger(LINKING_ENABLED, (isLinkingEnabled) ? 1 : 0);
		super.saveState(aMemento);
		commonManager.saveState(aMemento);
		commonViewer.getNavigatorContentService().saveState(aMemento);
	}
	/**
	 * <p>
	 * Force the workbench to focus on the Common Navigator tree.
	 * </p>
	 * 
	 * @see org.eclipse.ui.part.WorkbenchPart#setFocus()
	 */
	public void setFocus() {
		if (commonViewer != null) {
			commonViewer.getTree().setFocus();
		}
	}
	/**
	 * <p>
	 * Set the selection to the Common Navigator tree, and expand nodes if
	 * necessary. Use caution when invoking this method as it can cause