func (c Color256) Set() error {
	return SetTerminal(c.String())
}
Set terminal by 256 color code
package color
import (
	"fmt"
	"strconv"
	"strings"
)
const (
	TplFg256 = "38;5;%d"
	TplBg256 = "48;5;%d"
	Fg256Pfx = "38;5;"
	Bg256Pfx = "48;5;"
)
type Color256 [2]uint8
type Bit8Color = Color256  
var emptyC256 = Color256{1: 99}
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
}