5.0.28.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37520 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Saving of turtle's image.(#4721)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@37521 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e