Bump RSpec to 2.99
Convert specs to RSpec 2.99.2 syntax with Transpec

This conversion is done by Transpec 2.3.8 with the following command:
    transpec

* 10 conversions
    from: obj.should_receive(:message)
      to: expect(obj).to receive(:message)

* 9 conversions
    from: obj.should
      to: expect(obj).to

* 4 conversions
    from: == expected
      to: eq(expected)

* 2 conversions
    from: obj.stub(:message)
      to: allow(obj).to receive(:message)

* 1 conversion
    from: Klass.any_instance.stub(:message)
      to: allow_any_instance_of(Klass).to receive(:message)

For more details: https://github.com/yujinakayama/transpec#supported-conversions
Bump RSpec to 3.1.0+
Remove deprecated RSpec config setting
Explicitly delete RACK_ENV
Try travis_retry

Bundler is failing to install on rbx. :-(
Ditch travis_retry, don't use multiple jobs

The default on Travis is --jobs=3 but that was failing to install the
gems. See [this job](https://travis-ci.org/jc00ke/guard-puma/jobs/40717162) for
more details.
Merge pull request #14 from jc00ke/update-rspec

Update RSpec to 3.1.0+