Rainbows! 0.5.0

We depend on the just-released Unicorn 0.94.0 for the fixed
trailer handling.  As with `unicorn', the `rainbows' executable
now sets and respects ENV["RACK_ENV"].  Also small fixes and
cleanups including better FreeBSD 7.2 compatibility and
less likely to over-aggressively kill slow/idle workers
when a very low timeout is set.

Eric Wong (20):
      rev: split out heartbeat class
      bump Unicorn dependency to (consistently) pass tests
      tests: avoid single backquote in echo
      event_machine: avoid slurping when proxying
      tests: make timeout tests reliable under 1.9
      thread_pool: comment for potential SMP issue under 1.9
      Allow 'use "model"' as a string as well as symbol
      Rev model is the only user of deferred_bodies
      ev_core: use Tempfile instead of Unicorn::Util::tmpio
      ev_core: ensure quit is triggered on all errors
      rainbows: set and use process-wide ENV["RACK_ENV"]
      http_server: add one second to any requested timeout
      thread_pool: update fchmod heartbeat every second
      t0004: tighten up timeout test
      ev_core: remove Tempfile usage once again
      cleanup: remove unused t????.ru test files
      tests: staggered trailer upload test
      ensure RACK_ENV is inherited from the parent env
      t0100: more precise `expr` usage