Convert specs to RSpec 2.14.8 syntax with Transpec

Update RSpec suite to new expect syntax using the Transpec gem.

A few syntax types were excluded:

One liners - To enhance readability, one line it... should syntax blocks were ignored
Have Items - Instead of comparing against size, a test that expected have(number).items was kept
Its - Expectations of attrubutes on subject were not converted. This relates mostly to the one-liners.

A summary log of the changes can be found below. The complete changes are available in the diff.

All tests pass before and after the conversion.

This conversion is done by Transpec 2.3.4 with the following command:
    transpec --keep its --keep oneliner --keep have_items

* 122 conversions
    from: obj.should
      to: expect(obj).to

* 93 conversions
    from: == expected
      to: eq(expected)

* 10 conversions
    from: lambda { }.should
      to: expect { }.to

* 10 conversions
    from: obj.should_receive(:message)
      to: expect(obj).to receive(:message)

* 6 conversions
    from: obj.should_not
      to: expect(obj).not_to

* 6 conversions
    from: obj.stub(:message)
      to: allow(obj).to receive(:message)

* 5 conversions
    from: === expected
      to: be === expected

* 1 conversion
    from: obj.should_not_receive(:message)
      to: expect(obj).not_to receive(:message)

For more details: https://github.com/yujinakayama/transpec#supported-conversions