Testing Ruby 2.1.2p216

- Testing regression caused in Ruby GC
- http://hone.herokuapp.com/ruby/heroku/2014/09/17/a-call-for-help-testing-changes-to-ruby-21-gc.html
Merge pull request #266 from codetriage/bump-ruby-for-gc-testing

Testing Ruby 2.1.2p216
hashie breakup
Remove shoulda gems

- We are not using them in the tests.
- shoulda-context which is dependency of shoulda-matchers has a problem
  with  Ruby 2.2.0-preview1 which prevents us to upgrade to
  2.2.0-preview1.
- shoulda-context requires 'test/unit/testcase' which gives following
  error on Ruby 2.2.0-preview1 while running tests:

  $ rake test
  rake aborted!
  LoadError: cannot load such file -- test/unit/testcase
Merge pull request #269 from codetriage/rm-shoulda

Remove shoulda gems
Use Ruby 2.2.0 preview 1

- Updated kgio gem to latest version.
- Earlier version has problems in installation on Ruby 2.2.0-preview1
Bump to raindrops is also required for Ruby 2.2.0

- Reference: http://raindrops.bogomips.org/ChangeLog.html
Merge pull request #270 from codetriage/ruby22

Use Ruby 2.2.0 preview 1
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