Plot: Throughout last week leading dramatists, directors, actors, and designers from all over the world have been taking part in the Edinburgh International Drama Conference at the McEwan Hall, Edinburgh. Tonight's programme is a shortened version of yesterday's final session on The Theatre of the Future Is theatre design about to be permanently revolutionised? Is theatre moving back to its origins in dance and music? Is improvisation going to replace even more the settled text? Among those expected to take part: Lionel Bart, Jack Gelber, Eugene Ionesco, Joan Littlewood, Erwin Tiscator, J