initial actual streaming support
Convert specs to RSpec 3.0.2 syntax with Transpec

This conversion is done by Transpec 2.3.1 with the following command:
    transpec -f

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

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

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

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

* 5 conversions
    from: obj.should_not_receive(:message)
      to: expect(obj).not_to receive(:message)

* 2 conversions
    from: be_true
      to: be_truthy

* 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
spec cleanup
specs
reasonably functional streaming implementation