Replace Firefox with IceCat

We need to replace Firefox with the IceCat fork from http://www.gnu.org/software/gnuzilla/

By now, the sources at http://gnuzilla.gnu.org/download/debian/dists/deltah-icecat/main/source/ compile and run, but the resultant packages are very bloated -they include a lot of libraries provided by the system-.

We need to add them a loading wrapper, and a menu icon too.