Enhancements on SegueProtocol

[marcelofabri]

The goal of this PR is making implementing prepareForSegue easier.

To do so, some changes were necessary:

• SegueProtocol inherits from Equatable
• UIStoryboardSegue implements SegueProtocol (identifier is now optional to match UIStoryboardSegue declaration)

Now, you can do something like this:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if segue == ViewController.Segue.MySegue {

    }
}

[krzyzanowskim]

good job

[krzyzanowskim]

I missed this one. Why optional here ?

[marcelofabri]

Because UIStoryboardSegue already has an identifier property, which is optional.
As I wanted to make UIStoryboardSegue conform to SegueProtocol, this was the easiest way.

[krzyzanowskim]

thansks