#3668 - more robust fix - every GeoCasCell is evaluated by its output

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28775 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3045 fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28776 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3562 fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28777 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e