v0.9.0

Rainbows! 0.9.0

This release introduces compatibility with Sunshowers, a library
for Web Sockets, see http://rainbows.rubyforge.org/sunshowers
for more information.  Several small cleanups and fixes.

Eric Wong (20):
      add RevThreadPool to README
      rev: do not initialize a Rev::Loop in master process
      rainbows.1: update headers
      do not log IOError raised during app processing
      move "async.callback" constant to EvCore
      larger thread  pool default sizes ({Rev,}ThreadPool)
      ev_core: no need to explicitly close TmpIOs
      EventMachine: allow usage as a base class
      NeverBlock: resync with recent our EM-related expansion
      RevThread*: move warning message to a saner place
      EventMachineDefer: preliminary (and) broken version
      TODO: add EM Deferrables
      RevThread*: remove needless nil assignment
      README: HTML5 Web Sockets may not be supported, yet...
      env["hack.io"] for Fiber*, Revactor, Thread* models
      EventMachineDefer is experimental
      README: add Sunshowers reference
      Rakefile: resync with Unicorn
      doc/comparison: add Web Sockets to comparison
      README updates