func Log(format string, args ...interface{}) {
	if Verbose() {
		if len(args) > 0 {
			log.Printf(format+"\n", args...)
		} else {
			log.Println(format)
		}
	}
}
Log calls Printf(format, args...) iff Verbose() returns true.
package verbose
import (
	"log"
	"github.com/attic-labs/kingpin"
)
var (
	verbose bool
	quiet   bool
)
func RegisterVerboseFlags(app *kingpin.Application) {
	verbose = false
	quiet = false
	app.Flag("verbose", "show more").Short('v').BoolVar(&verbose)
	app.Flag("quite", "show less").Short('q').BoolVar(&quiet)
}
func Verbose() bool {
	return verbose
}
func SetVerbose(v bool) {
	verbose = v
}
func Quiet() bool {
	return quiet
}
func SetQuiet(q bool) {
	quiet = q
}