Assegnate 5 su 5 stelle

This is a great extension, but as some people already mentioned it is not compatible with Thunderbird 3.0. I created an updated build which you can get at http://www.shroomery.org/ythan/habu-1.8.6.5a-tb.xpi. Please understand that I'm not the original author and this is an unofficial, unsupported release. But for the time being it seems to work well enough for me. :)