Get team_token from the RTS on login

Use the /login endpoint of the RTS to get the team token when the user has successfully logged in.

src/components/structures/MatrixChat.js

@@ -210,6 +210,8 @@ module.exports = React.createClass({
         window.addEventListener('resize', this.handleResize);
         this.handleResize();
 
+        Lifecycle.initRtsClient(this.props.config.teamServerConfig.teamServerURL);
+
         // the extra q() ensures that synchronous exceptions hit the same codepath as
         // asynchronous ones.
         q().then(() => {