It may have been a weeknight, but I saw that as no reason to stay in.  Anytime of any day or night is a good time for rock and roll, but last Thursday was a particularly noteworthy occasion.  One of the most exciting guitarists around was in town at the Fox Theatre, and I wasn't about to miss him.  I'm talking about Luther Dickinson, shredder-extraordinaire of the North Mississippi Allstars, and more recently, of a little side project that