save to ggbtube if user is logged in.
save file on device/download file if there's no network connection.

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35624 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
no "description" and "tags" for private files

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35625 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e