nnnrss: an nnfeed-based rss-method

[Joshua Barrett]

nnrss was giving me grief, so I wrote a new version based on nnfeed. I hacked 
this together in about a day after reading
the source code for nnatom and nnfeed, so it's probably not the most robust. 
However, at this point it works well enough
that I've started actually using it as my method for RSS feeds, so I thought it 
might be of interest to some of
you. Code is at https://github.com/jjbarr/nnnrss.