Bug 113239 new compiler option 'fatalOptionalError'
* COMPILER / Treating Optional Error as Fatal * When enabled, optional errors (i.e. optional problems which severity is set to "error") will be treated as standard * compiler errors, yielding problem methods/types preventing from running offending code until the issue got resolved. * When disabled, optional errors are only considered as warnings, still carrying an error indication to make them more * severe. Note that by default, errors are fatal, whether they are optional or not. * - option id: "org.eclipse.jdt.core.compiler.problem.fatalOptionalError" * - possible values: { "enabled", "disabled" } * - default: "enabled" </pre>
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/OptionsConfigurationBlock.java
public String getStoredValue(IScopeContext[] lookupOrder, boolean ignoreTopScope, IWorkingCopyManager manager) {
			for (int i= ignoreTopScope ? 1 : 0; i < lookupOrder.length; i++) {
				String value= getStoredValue(lookupOrder[i], manager);
				if (value != null) {
					return value;
				}
			}
			return null;
		}
		
		public void setStoredValue(IScopeContext context, String value, IWorkingCopyManager manager) {
			if (value != null) {
				getNode(context, manager).put(fKey, value);
			} else {
				getNode(context, manager).remove(fKey);
			}
		}
			
		/* (non-Javadoc)
		 * @see java.lang.Object#toString()
		 */
		public String toString() {
			return fQualifier + '/' + fKey;
		}
		public String getQualifier() {
			return fQualifier;
		}
	}
	
	protected static class ControlData {