Parley: Federated, decentralised chat that speaks plain IRC

With several people sharing a nick across instances, a channel mention of one of them pushes a notification to all of them. ## Cause `namesAccount` counted a name as a mention wherever the nick stood on its own, and a colon ends a word. So with a `bob` on foo.com and another on bar.com in one room: - `bob:bar.com: lunch?` typed on foo.com woke both bobs, not just bar's. - A bare `bob: lunch?` from...