[xml] Broken links on xmlsoft.org/downloads.html

[Wim Lewis <wiml omnigroup com>]

The "Gnome SVN base" link goes to a viewvc page, but there doesn't  
seem to be a link anywhere to the SVN repository itself. (Trying to  
check out the "svn base" link produces an odd error:

> % svn co http://svn.gnome.org/viewvc/libxml2/trunk/
> svn: Repository moved temporarily to '/viewvc/libxml2/trunk/';  
> please relocate


) Also, the "Gnome SVN tools" link goes to a 404 ("The requested URL / 
tools/svn.html was not found on this server.").