Direct messages column (#4514)

* Added a timeline for Direct statuses
* Lists all Direct statuses you've sent and received
* Displayed in Getting Started
* Streaming server support for direct TL

* Changes to match other timelines in 2.0

app/javascript/mastodon/actions/compose.js

@@ -145,6 +145,8 @@ export function submitCompose() {
       if (response.data.in_reply_to_id === null && response.data.visibility === 'public') {
         insertIfOnline('community');
         insertIfOnline('public');
+      } else if (response.data.visibility === 'direct') {
+        insertIfOnline('direct');
       }
     }).catch(function (error) {
       dispatch(submitComposeFail(error));