Add MemberPresenceAvatar and control presence ourselves

Includes rudimentary support for custom statuses and user-controlled status. Some minor tweaks have also been made to better control how we advertise our presence.

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

src/MatrixClientPeg.js

@@ -93,6 +93,7 @@ class MatrixClientPeg {
         const opts = utils.deepCopy(this.opts);
         // the react sdk doesn't work without this, so don't allow
         opts.pendingEventOrdering = "detached";
+        opts.disablePresence = true; // we do this manually
 
         try {
             const promise = this.matrixClient.store.startup();