[Bianculli here: Wimbledon tennis is available all weekend, regardless of weather, thanks to the new retractable center court roof. Men's semis are televised live Friday by ESPN2 (7 a.m. ET) and NBC (noon ET). Women's finals are Saturday at 9 a.m. ET, and the men's on Sunday at the same time, both on NBC. And at the climax of these weeks of British tennis, contributing columnist Diane Holloway salutes one of its amiable, always professional sportscasters...] Dick Enberg meets every