Move dispatcher into a subdirectory

We're expecting to have a whole bunch of types for the dispatched payloads, so pull the thing into a directory we can throw them in.

src/Lifecycle.js

@@ -26,7 +26,7 @@ import Analytics from './Analytics';
 import Notifier from './Notifier';
 import UserActivity from './UserActivity';
 import Presence from './Presence';
-import dis from './dispatcher';
+import dis from './dispatcher/dispatcher';
 import DMRoomMap from './utils/DMRoomMap';
 import Modal from './Modal';
 import * as sdk from './index';