While his star turns in Terms of Endearment and The Squid and the Whale suggested a softer side, we had no idea that the still waters of Jeff Daniels ran quite so deep. Turns out the actor has been compiling a cache of folk songs over the past 30 years, and will be showcasing them at Wolftrap tonight. While it’d be fun to rake Dumb (or was he Dumber?) over the coals for doing the…