mention read-only svn access

doc/gmsh.html

@@ -84,9 +84,10 @@ launch: use at your own risk!):
         (<a href="/gmsh/bin/MacOSX/nightly.log">build log</a>)
       <li>nightly <a href="/gmsh/src/gmsh-nightly-source.tgz">source
           snapshot</a>
+      <li>read-only svn access: <code>svn co https://geuz.org/svn/gmsh/trunk
+          gmsh</code> (username: gmsh, password: gmsh)
     </ul>
-<li>
-Browse all versions: <a href="/gmsh/bin/">binaries</a>
+  <li>Browse all versions: <a href="/gmsh/bin/">binaries</a>
     and <a href="/gmsh/src/">sources</a>
 </ul>