Cake, praise and tears were on exhibit Tuesday evening at the Umpqua Valley Arts Center in Roseburg. About 50 art patrons thanked and said goodbye to Kathy Henderson, who guided the center through an economic recovery. “She took a flailing ship and pulled a team together to get it going in a good direction,” said Aleta McGee, manager of the center’s four galleries. Henderson’s three-year stint as executive director of the Umpqua Valley Arts Association will end Nov. 2 when she departs to become executive director of the Salem Downtown Partnership. Under Henderson, the center gained a place on the …