Convert specs to RSpec 2.99.1 syntax with Transpec

This conversion is done by Transpec 2.3.6 with the following command:
    transpec -f

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

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

* 10 conversions
    from: be_false
      to: be_falsey

* 10 conversions
    from: be_true
      to: be_truthy

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

* 5 conversions
    from: describe 'some model' { }
      to: describe 'some model', :type => :model { }

* 4 conversions
    from: describe 'some controller' { }
      to: describe 'some controller', :type => :controller { }

* 4 conversions
    from: obj.should_not
      to: expect(obj).not_to

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

* 3 conversions
    from: describe 'some feature' { }
      to: describe 'some feature', :type => :feature { }

* 2 conversions
    from: describe 'some helper' { }
      to: describe 'some helper', :type => :helper { }

* 2 conversions
    from: its(:attr) { }
      to: describe '#attr' do subject { super().attr }; it { } end

* 1 conversion
    from: it { should_not ... }
      to: it { is_expected.not_to ... }

For more details: https://github.com/yujinakayama/transpec#supported-conversions
upgrade to rspec 3!
remove depricated rspec/autorun
remove unnecessary code due to transpec
use its gem instead of super
Merge pull request #242 from rubycorns/upgrade-rspec

Upgrade rspec