Say it ain't so. Could Tim Gunn not be back for the next installment of Project Runway ? It's a chilling thought and, while it might pale in comparison to the real troubles of the world today, it's one that gives this Runway obsessive a bit of a difficulty breathing. (Rest assured, Heidi Klum, Michael Kors, and--say it with me--Nina Garcia are all locks for next season.) This week's edition of industry bible Entertainment Weekly has the story. According to the article's writer Nisha Gopalan, Bravo--the style-hungry network behind Project Runway --is champing at the bit to get started on the fourth season of the sartorial challenge. One speed bump in the road to Season Four just happens to be Tim Gunn himself. Whah? You'd be right to ask that, especially given that I can't imagine a single episode of Runway sans Gunn, much less an entire season. While Gunn's not commenting one way or another, he's a busy guy as the chair of the fashion design depar