Convert specs to RSpec 2.99.0 syntax with Transpec

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

* 46 conversions
    from: it { should ... }
      to: it { is_expected.to ... }

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

* 1 conversion
    from: describe 'some controller' { }
      to: describe 'some controller', :type => :controller { }

* 1 conversion
    from: describe 'some request' { }
      to: describe 'some request', :type => :request { }

For more details: https://github.com/yujinakayama/transpec#supported-conversions