macaron.go
func NewWithLogger(out io.Writer) *Macaron {
	m := &Macaron{
		Injector: inject.New(),
		action:   func() {},
		Router:   NewRouter(),
		logger:   log.New(out, "[Macaron] ", 0),
	}
	m.Router.m = m
	m.Map(m.logger)
	m.Map(defaultReturnHandler())
	m.NotFound(http.NotFound)
	m.InternalServerError(func(rw http.ResponseWriter, err error) {
		http.Error(rw, err.Error(), 500)
	})
	return m
}
func NewWithLogger(out io.Writer) *Macaron {
	m := &Macaron{
		Injector: inject.New(),
		action:   func() {},
		Router:   NewRouter(),
		logger:   log.New(out, "[Macaron] ", 0),
	}
	m.Router.m = m
	m.Map(m.logger)
	m.Map(defaultReturnHandler())
	m.NotFound(http.NotFound)
	m.InternalServerError(func(rw http.ResponseWriter, err error) {
		http.Error(rw, err.Error(), 500)
	})
	return m
}
// NewWithLogger creates a bare bones Macaron instance.
// Use this method if you want to have full control over the middleware that is used.
// You can specify logger output writer with this function.