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/internal/navigator/extensions/NavigatorContentDescriptor.java
.length() > 0) ? Boolean.valueOf(activeByDefaultString)
				.booleanValue() : true;
		String providesSaveablesString = configElement
			.getAttribute(ATT_PROVIDES_SAVEABLES);
		providesSaveables = (providesSaveablesString != null && providesSaveablesString
				.length() > 0) ? Boolean.valueOf(providesSaveablesString)
						.booleanValue() : false;
		appearsBeforeId = configElement.getAttribute(ATT_APPEARS_BEFORE);
		if (priorityString != null) {
			try {
				Priority p = Priority.get(priorityString);
				priority = p != null ? p.getValue()
						: Priority.NORMAL_PRIORITY_VALUE;
			} catch (NumberFormatException exception) {
				priority = Priority.NORMAL_PRIORITY_VALUE;
			}
		}
		
		 
		
		sequenceNumber = priority;
		String sortOnlyString = configElement.getAttribute(ATT_SORT_ONLY);
		sortOnly = (sortOnlyString != null && sortOnlyString.length() > 0) ? Boolean.valueOf(
				sortOnlyString).booleanValue() : false;
		
		if (id == null) {
			throw new WorkbenchException(NLS.bind(
					CommonNavigatorMessages.Attribute_Missing_Warning,
					new Object[] {
							ATT_ID,