Convert specs to the latest RSpec syntax with Transpec

This conversion is done by Transpec 1.3.0 with the following command:
    transpec -m

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

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

* 10 conversions
    from: stub('something')
      to: double('something')

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

* 4 conversions
    from: obj.stub(:message => value)
      to: allow(obj).to receive(:message).and_return(value)

* 2 conversions
    from: Klass.any_instance.stub(:message)
      to: allow_any_instance_of(Klass).to receive(:message)

* 1 conversion
    from: expect(collection).to have_at_least(n).items
      to: expect(collection.size).to be >= n

* 1 conversion
    from: expect(obj).to have(n).endpoints
      to: expect(obj.endpoints.size).to eq(n)
Don't allow 2.0 failures.
Allow cane to be installed on 2.0.
Merge pull request #36 from seomoz/build-on-2.0

Build on 2.0