Convert specs to RSpec 3 syntax (using transpec)

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

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

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

* 49 conversions
    from: obj.stub(:message => value)
      to: allow(obj).to receive_messages(:message => value)

* 27 conversions
    from: =~ [1, 2]
      to: match_array([1, 2])

* 13 conversions
    from: obj.should_not
      to: expect(obj).not_to

* 2 conversions
    from: lambda { }.should
      to: expect { }.to

* 1 conversion
    from: >= expected
      to: be >= expected

For more details: https://github.com/yujinakayama/transpec#supported-conversions