Revert PR#131

[unakatsuo]

recent changes for http gem breaks reel. it is good to keep the dependency on 0.5.x series.

websocket_parser gem has left http gem since v0.16.0 release. I believe that #131 was just needed to bump websocket_parser gem version.

Reel's master branch build started to fail after the PR tarcieri/http#80 because of the removal of lib/http/header.rb.

Build log for master HEAD (5ee0ae49ac76a8e45a) https://travis-ci.org/unakatsuo/reel/jobs/19233177

$ bundle install
$ bundle exec rake
/home/travis/.rvm/rubies/ruby-2.0.0-p353/bin/ruby -S rspec ./spec/reel/connection_spec.rb ./spec/reel/http_server_spec.rb ./spec/reel/https_server_spec.rb ./spec/reel/response/writer_spec.rb ./spec/reel/response_spec.rb ./spec/reel/websocket_spec.rb
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[Coveralls] Using SimpleCov's default settings.
/home/travis/build/unakatsuo/reel/lib/reel/response.rb:5:in `<class:Response>': uninitialized constant HTTP::Header (NameError)
    from /home/travis/build/unakatsuo/reel/lib/reel/response.rb:4:in `<module:Reel>'
    from /home/travis/build/unakatsuo/reel/lib/reel/response.rb:3:in `<top (required)>'

[tarcieri]

Can you better describe the breakage you're experiencing? Reel CIs against the http gem master, so if there's a problem it indicates a lack of coverage in the test suite.

[unakatsuo]

I have added the details.

[Asmod4n]

Currently, when you have

gem 'http', github: 'tarcieri/http'
gem 'reel', github: 'celluloid/reel'

in your Gemfile, reel doesn't start.

uninitialized constant HTTP::Header
/home/xxx/.gem/ruby/2.1.0/bundler/gems/reel-5ee0ae49ac76/lib/reel/response.rb:5:in `<class:Response>'

HTTP::Headers is now a Class, so you can't include it anymore —_—

[tarcieri]

We should update Reel to be compatible with the new HTTP Gem API rather than trying to roll back to the antiquated version.