Added a section for the source code repository in the download page.
This follows a message by Edward at: https://mail.gna.org/public/relax-devel/2011-06/msg00078.html Message-id: <BANLkTimq=4vfngu+u2WBAuTTsS0nMW+B4A@...>
Authored by: semor 2011-06-10
Parent: [r12960]
Child: [r12962]
