upgrade to rspec 3
Convert specs to RSpec 3.0.0 syntax with Transpec

This conversion is done by Transpec 2.2.1 with the following command:
    transpec

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

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

* 1 conversion
    from: =~ /pattern/
      to: match(/pattern/)

* 1 conversion
    from: obj.should_receive(:message)
      to: expect(obj).to receive(:message)

For more details: https://github.com/yujinakayama/transpec#supported-conversions
no longer using DRB. KISS.
version bump to 1.3.0