Bugfix: Indexing of Experiments in ES work again

Because the experiment mapping in ES sets the routing path to id and required to True,
 the id has to be in the document for the indexing to work. Now the id is also added to the
 document
Feature: Add a dynamic favicons which show unread notifications

A custom favicon was added to the site. In additional to this a small js library
(http://lab.ejci.net/favico.js/) that allows to dynamically add badges to the favicon and
a simple GWT wrapper (Favico.java and FaviconOptions.java) were added.
The favicon now shows the same badge as the My Account menu.