feature suggestion: detect mp3 download links, add as enclosures

[hjwp]

What I really want is to have my podcast fetcher pull down mixcloud mixes to my phone for me to listen to offline. So, for bonus points, this app (in a perfect world) would:

• scan the description/info content of a mixcloud entry
• look for any external hyperlinks that seem to point to mp3 files (maybe just look at file extension)
• include links to those in the "audio enclosures" part of the rss xml.

magic! i don't know node or i'd have a crack myself.