Fix a typo

modules/UI/toolbars/Toolbar.js

     'invite': '#toolbar_button_link',
     'chat': '#toolbar_button_chat',
     'prezi': '#toolbar_button_prezi',
-    'ethherpad': '#toolbar_button_etherpad',
+    'etherpad': '#toolbar_button_etherpad',
     'fullscreen': '#toolbar_button_fullScreen',
     'settings': '#toolbar_button_settings',
     'hangup': '#toolbar_button_hangup'
     return my;
 }(Toolbar || {}));
 
-module.exports = Toolbar;
+module.exports = Toolbar;