experimenting with suspension of requestCycle via servlet 3 async Notes: - enabled async-supported in web.xml for ComponentReferenceApplication - LinkPage shows usage of RequestCycle#suspend() - pageAccessSynchronizer uses the requestCycle instead of the thread now, since two threads might process a page (PageAccessSynchronizerTest still fails) - ServletWebRequest must not call httpServletRequest#getContextPath(), since it returns null during async processing