Contemporary dance has come a hell of a long way in the 30 years that Dance Umbrella has been running and that's reflected in this year's programme with the once pioneering and avant garde, now established, respectable big hitters opening the season: Merce Cunningham dance company presents new work alongside classic at the Barbican and Richard Alston celebrates his 60th birthday at Sadlers Wells. As usual, "brief encounters" with emerging choreographers precede the big......