TORONTO - Chris Martin and Johnny Buckland of Coldplay literally stopped traffic with their appearance at 102.1 the Edge’s street-level broadcast studio at 228 Yonge Street yesterday. So many fans gathered that the band’s SUV had to be escorted down the street by mounted police officers. Just days after tickets for Coldplay’s Kool Haus show sold out in minutes, 102.1 the Edge announced that Chris and Johnny would drop by for an exclusive performance. This would be the first time Canadian Coldplay fans would have a chance to hear material from the group’s much-anticipated new album, X&Y, which isn’t due...