Removal of Podcasts from DTN

Per Tom, removing Shut Up Sit Down, How to Play, and Gamer's Atlas.  To
do this, I just commented out the HTML for now in case they wind up
coming back.  If enough time passes and they don't come back, I'll
remove the HTML completely.
Merge pull request #38 from dicetower/Rob-RemovePodcasts

Removal of Podcasts from DTN