Updated specs to RSpec 2.14.8 syntax with Transpec.

This conversion is done by Transpec 2.1.0 with the following command:
    transpec

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

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

See also: https://github.com/yujinakayama/transpec#supported-conversions