handling empty datastream_id


git-svn-id: svn://oss.beweb.dbc.dk/sync_php/php/OpenLibrary/OpenSearch/trunk@76947 30e9dc4a-7611-4fbc-83ba-eecf79b76bd0
sort groups


git-svn-id: svn://oss.beweb.dbc.dk/sync_php/php/OpenLibrary/OpenSearch/trunk@76950 30e9dc4a-7611-4fbc-83ba-eecf79b76bd0
wait with multiple fields in solr formats


git-svn-id: svn://oss.beweb.dbc.dk/sync_php/php/OpenLibrary/OpenSearch/trunk@76964 30e9dc4a-7611-4fbc-83ba-eecf79b76bd0