Download .ggb (#2638)
 * ggb added on the end of the filename
 * "Save as" label added

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@22931 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
XSD update

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@22932 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e