support escape char

slice_common.go:
const escape_char = '\\'
func searchPart(value string, stop rune) (bool, string) {
	var result string
	escape := false
	for _, char := range value {
		if escape {
			result += string(char)
			escape = false
		} else if char == escape_char {
			escape = true
		} else if char != stop {
			result += string(char)
		} else {
			return true, result
		}
	}
	return false, result
}