BreakerEvent now implements Stringer interface

[beono]

Hello

Thanks for the library.
I added implementation of Stringer interface for BreakerEvent.

Usage example:

ch := builder.cb.Subscribe()
	go func() {
		for {
			e := <- ch
			fmt.Println(e) // prints nice message instead of a numeric value
		}
	}()

[beono]

Hello @rubyist,

Do you still maintain the repo?