Earnest play serves a slice of tennis ace's complex life by Ed Siegel
WILLIAMSTOWN -- The tennis champion Bill Tilden used to write stories, novels, and plays with titles like ''Foot Fault'' that conjured up the sport he mastered. If A.R. Gurney had followed suit in his new play, which is receiving its world premiere here, it would be called ''The Love That Dare Not Speak Its Name.'' Or just ''Out!''