Update to RSpec 3.0. Also update rake, etc.
Convert specs to RSpec 3.0.0 syntax with Transpec

This conversion is done by Transpec 2.2.4 with the following command:
    transpec -f

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

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

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

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

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

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

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