#3977: [desktop] Offline mode without login and OpenFromGGT 

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31054 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#3950 improvement

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@31055 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e