Fix event_menu importer
Fix event_menu importer

- use NULL for default titles
- handle empty titles
- use the correct names for vc/chat entries

mic4ael/indico,pferreir/indico,indico/indico,indico/indico,OmeGak/indico,mvidalgarcia/indico,DirkHoffmann/indico,DirkHoffmann/indico,ThiefMaster/indico,mvidalgarcia/indico,mvidalgarcia/indico,mic4ael/indico,OmeGak/indico,ThiefMaster/indico,OmeGak/indico,indico/indico,OmeGak/indico,mic4ael/indico,pferreir/indico,DirkHoffmann/indico,mic4ael/indico,pferreir/indico,ThiefMaster/indico,ThiefMaster/indico,mvidalgarcia/indico,pferreir/indico,DirkHoffmann/indico,indico/indico