yahns 0.0.3 - more bugfixes, still working!

There are several important bugfixes around graceful shutdown.
The shutdown_timeout directive should work more consistently
and work even if an app is streaming/trickling slowly to
a client.

This also plugs an odd FD leak in response buffering.

There's also some internal comments/documentation for folks
reviewing the strange internals of yahns.

Otherwise, it seems to be capable of serving its own website,
http://yahns.yhbt.net/README quite well.

Rack application authors merely need to write code as if they have a
gun to their head if they expect to keep code running on yahns.
Again, yahns is extremely intolerant of bugs in the applications
it hosts.  Otherwise I'm comfortable in the stability of yahns
itself.

Eric Wong (17):
      http_client: do not dump backtrace on ETIMEDOUT
      ensure we close response body if buffering caught up
      http_response: reorder wbuf_maybe on successful early flush
      wbuf: document reasoning for the design of these clases
      build: improve NEWS generation, add atom feed
      exec_cgi: release pipe/pid sooner
      SIGWINCH works after SIGUSR2 upgrades
      shutdown_timeout works around long-running response/apps
      doc: recommend worker_processes if the app uses SIGCHLD
      fdmap: simplify IO expiry interface
      fdmap: document + fix for level-trigger
      queue_epoll: document epoll concurrency caveats
      doc: caution users against disabling buffering
      queue: eliminate :wait_readwrite
      test: exec_cgi test uses worker_processes
      test_server: remove unneccessary IO#wait call
      test: workaround sockets not being binary on rbx