redundant hostnames and obsolete urchin.js

[Federico Bruni]

I've started looking at Analytics, which gives two warnings:

1. We are using the old script urchin.js, which was replaced by 
analytics.js

$ git grep urchin.js
scripts/build/website_post.py:<script 
src="http://www.google-analytics.com/urchin.js";

https://developers.google.com/analytics/devguides/collection/analyticsjs/


2. Redundant hostnames
Currently it's possible to visit either lilypond.org and 
www.lilypond.org.
We should make a choice and set up a 301 redirect in Apache htaccess.

I'm for lilypond.org (without www). This was recently discussed when 
talking about the tagline:
http://lists.gnu.org/archive/html/lilypond-devel/2016-02/msg00148.html

Please confirm the above and I'll make a patch.

Thanks
Federico