func (c Color256) Printf(format string, a ...interface{}) {
	fmt.Print(RenderString(c.String(), fmt.Sprintf(format, a...)))
}
Printf format and print message
package color
import (
	"fmt"
	"strings"
)
const (
	TplFg256 = "38;5;%d"
	TplBg256 = "48;5;%d"
)
type Color256 [2]uint8
func Bit8(val uint8, isBg ...bool) Color256 {
	return C256(val, isBg...)
}
func C256(val uint8, isBg ...bool) Color256 {
	bc := Color256{val}
	if len(isBg) > 0 && isBg[0] {
		bc[1] = AsBg
	}
	return bc
}
func (c Color256) Print(a ...interface{}) {
	fmt.Print(RenderCode(c.String(), a...))
}