Coming midway through Matthew McConaughey’s Acting RenaissanceTM, “Mud” lovingly creates a nostalgic view of the American South, drenched in golden sunset hues. It’s a gently paced coming-of-age drama telling the story of two young teenagers, Ellis and Neckbone, from DeWitt, Arkansas who have found a derelict boat stuck halfway up a tree on a small Mississippi River island. Intending to claim it,…