development mode does not recognize changes in parent flows

Activating development mode according to http://docs.spring.io/spring-webflow/docs/current/reference/htmlsingle/#builder-development to true shoud 'switch on hot-reloading of flow definition changes'. Unfortunately this does not work, if not the flow itself, but it's parent flow definition is changed. If the file itself is not changed, parent flows should be checked, too.

From the perspective of XmlFlowModelBuilder.hasFlowModelResourceChanged(): If this resource's lastModified is not bigger than lastModifiedTimestamp, it should check its parent's lastModified value and it's parent's parents.