Bug 126414 [Commands] handlers: Provide help context ids
For commands and handlers to replace actions, they need to be capable of providing help context identifiers. For an example, see OpenResourceHandler in org.eclipse.ui.ide. This help context id will need to be definable through XML and through code.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java
stringBuffer.append(',');
			stringBuffer.append(category);
			stringBuffer.append(',');
			stringBuffer.append(handler);
			stringBuffer.append(',');
			stringBuffer.append(parameters);
			stringBuffer.append(',');
			stringBuffer.append(returnType);
			stringBuffer.append(',');
			stringBuffer.append(defined);
			stringBuffer.append(')');
			string = stringBuffer.toString();
		}
		return string;
	}
	/**
	 * Makes this command become undefined. This has the side effect of changing
	 * the name and description to <code>null</code>. This also removes all
	 * state and disposes of it. Notification is sent to all listeners.
	 */
	public final void undefine() {
		string = null;
		final boolean definedChanged = defined;
		defined = false;
		final boolean nameChanged = name != null;
		name = null;
		final boolean descriptionChanged = description != null;
		description = null;
		final boolean categoryChanged = category != null;
		category = null;