Fix '\t' (byte(9)) in multiline string is invalid

[electricface]

package main

import (
	"fmt"
	"log"

	"github.com/titanous/json5"
)

type Struct struct {
	Str string
}

func main() {
	log.SetFlags(log.Lshortfile)

	var err error
	content := []byte(`{"Str":"hello\
 	abc"}`)
	var st Struct
	err = json5.Unmarshal(content, &st)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(st.Str)
}

// error json5.go:23: invalid character '\t' in string literal