[Nml-wg] is alias

FYI, at the conference call today we decide to rename the "alias" relation to "isalias" per https://forge.ogf.org/sf/go/artf6538 Freek (PS: sorry to spam your mailbox like this, I'm just trying to make sure that everything that is discussed at conferences or calls is replicated on the list, as per policy http://www.ogf.org/pipermail/nml-wg/2009-June/000270.html).