add cancelButton to simpleHeader

src/components/structures/MatrixChat.js

@@ -1025,6 +1025,7 @@ module.exports = React.createClass({
 
     onUserSettingsClose: function() {
         // XXX: use browser history instead to find the previous room?
+        // or maintain a this.state.pageHistory in _setPage()?
         if (this.state.currentRoom) {
             dis.dispatch({
                 action: 'view_room',

src/components/structures/UserSettings.js

@@ -340,7 +340,7 @@ module.exports = React.createClass({
 
         return (
             <div className="mx_UserSettings">
-                <SimpleRoomHeader title="Settings"/>
+                <SimpleRoomHeader title="Settings" onCancelClick={ this.props.onClose }/>
 
                 <GeminiScrollbar className="mx_UserSettings_body" autoshow={true}>