Add messages about us stopping active maintainance of snowball.
Add a link to the source on github.


git-svn-id: svn://snowball.tartarus.org/snowball/trunk@586 633ccae0-01f4-0310-8c99-d3591da6f01f
Remove text on front page asking for all correspondance to be addressed to the
mailing list


git-svn-id: svn://snowball.tartarus.org/snowball/trunk@587 633ccae0-01f4-0310-8c99-d3591da6f01f