tiny non-interactive NNTP client

 sinntp is a tiny NNTP client originally designed to work in non-interactive
 mode. Following commands are supported:
  - nntp-push: sending articles to the server,
  - nntp-pull: fetching new articles to the mbox file,
  - nntp-list: listing available newsgroups,
  - nntp-get: downloading individual messages in RFC822 format.