Add option to not send read receipts.

Addresses element-hq/element-web#2527.

The side effect of this is that notifications remain stuck. Because the RR isn't sent, the unread notification stays on the client. This also ends up affecting riot-android, and likely riot-ios.

Signed-off-by: Travis Ralston <travpc@gmail.com>

src/components/structures/TimelinePanel.js

@@ -28,6 +28,7 @@ var ObjectUtils = require('../../ObjectUtils');
 var Modal = require("../../Modal");
 var UserActivity = require("../../UserActivity");
 var KeyCode = require('../../KeyCode');
+import * as UserSettingsStore from "../../UserSettingsStore";
 
 var PAGINATE_SIZE = 20;
 var INITIAL_SIZE = 20;
@@ -494,6 +495,7 @@ var TimelinePanel = React.createClass({
         // very possible have logged out within that timeframe, so check
         // we still have a client.
         if (!MatrixClientPeg.get()) return;
+        if (UserSettingsStore.getSyncedSetting('dontSendReadReceipts', false)) return;
 
         var currentReadUpToEventId = this._getCurrentReadReceipt(true);
         var currentReadUpToEventIndex = this._indexForEventId(currentReadUpToEventId);

src/components/structures/UserSettings.js

@@ -44,6 +44,10 @@ const SETTINGS_LABELS = [
         id: 'autoplayGifsAndVideos',
         label: 'Autoplay GIFs and videos',
     },
+    {
+        id: 'dontSendReadReceipts',
+        label: "Don't send read receipts"
+    },
 /*
     {
         id: 'alwaysShowTimestamps',