Convert specs to RSpec 3.0.2 syntax with Transpec

This conversion is done by Transpec 2.3.1 with the following command:
    transpec -f

* 7 conversions
    from: be_true
      to: be_truthy

* 6 conversions
    from: be_false
      to: be_falsey

* 1 conversion
    from: obj.should_receive(:message)
      to: expect(obj).to receive(:message)

* 1 conversion
    from: obj.stub(:message => value)
      to: allow(obj).to receive_messages(:message => value)

For more details: https://github.com/yujinakayama/transpec#supported-conversions

use true/false instead of truthy/falsey