Make sure Tube API parser does not choke on new flexible worksheets

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34702 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Automatic update of propset svn:ignore via for svnignore.txt's by svnignore

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@34703 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e