js16进制跟字符串互转的时候是在是太麻烦了，干脆写个备用
Usage: python filename.py -e [--encode] str -d [--decode] hex_str
python hex_str_tool.py -e x1z3tg.ceye.io
>> \x78\x31\x7a\x33\x74\x67\x2e\x63\x65\x79\x65\x2e\x69\x6f
python hex_str_tool.py -d \x78\x31\x7a\x33\x74\x67\x2e\x63\x65\x79\x65\x2e\x69\x6f
>> x1z3tg.ceye.io