Fixing validation errors on the feed

http://validator.w3.org/feed/check.cgi?url=http%3A%2F%2Frefinedbitspodcast.com%2Ffeed.xml

I went ahead and listed myself as managing editor and webmaster. I did so because it recommends having a real name, but we could also make it "Refined Bits" if you'd rather.

I put "yes" for the explicit value mainly because have guests and we don't want to censor them. I'm not sure if we've actually used any explicit language though.

It also recommends only having one enclosure, which means only one audio source. I went with mp3, since it has the best client support.