Add default locator endpoint
Improve locator
Now there is no need to write descriptions for services.

Example:
    s := cocaine.NewService("storage")
    res := <-s.Call(3, "apps", []string{"app"})
    var list []string
    res.Extract(&list)
    fmt.Println(list)
Notify goroutines about Service.Close()
Call service methods by name
Log not only strings. Allow ...interface{} like log.Println()
codec package doesn't throw io.EOF - so give up this chcking