Nicer date output for materials

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26568 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
File browser improvements

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26569 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e