Update rspec-rails to 3.0.2
Convert specs to RSpec 3.0.4 syntax with Transpec

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

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

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

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

* 5 conversions
    from: it { should_not ... }
      to: it { is_expected.not_to ... }

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

* 3 conversions
    from: it { should have(n).items }
      to: it 'has n posts' do expect(subject.size).to eq(n) end

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

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

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

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

* 1 conversion
    from: expect { }.should
      to: expect { }.to

For more details: https://github.com/yujinakayama/transpec#supported-conversions
Remove cane
Update rubocop to 0.25.0
Update spring and spring-commands-rspec
Update capybara to 2.4.1
Remove minitest
Update shoulda-matchers to 2.6.2
Update simplecov to 0.9.0