instanceof GeoPolyhedron >> .isGeoPolyhedron()

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31320 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
4.9.240.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31321 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Better handling of labelVisible

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31322 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e