base91编码与解码

base91 encode and decode

修改自Joachim Henke的php代码，查看 http://base91.sourceforge.net/

Modified from Joachim Henke's php code, see at http://base91.sourceforge.net/

使用例 | How to use

base91Encode("abcdefgHIJKLMN0123456789!@$%^&*()-=<>?:{}");
// return "#G(Ic,5p(5qOdwQb?texAkZdx2G?*NyWqOa16dvz{0&_t[rU`]D"

base91Decode("#G(Ic,5p(5qOdwQb?texAkZdx2G?*NyWqOa16dvz{0&_t[rU`]D")
// return "abcdefgHIJKLMN0123456789!@$%^&*()-=<>?:{}"