Adding Google Analytics

If I remember correctly, yacs provides native support for Urchin, which is the previous name for Google Analytics. All you have to do is to enter the id to use in the configuration panel for services. This will set the global parameter google_urchin_account and yacs will do the rest. If this is still working, then it would be better to use this feature. Else, if this way to invoke Google Analytics has been obsoleted, we should remove related code. Thanks for your feed-back on this!