Exeption with wrong message

```sh
node -e 'console.log(require("js-yaml").safeLoad("!<?\u0000[0]"))'

js-yaml/lib/js-yaml/type/int.js:90
    if (!isDecCode(data.charCodeAt(index))) {
                        ^

TypeError: data.charCodeAt is not a function
```

I guess it should throw, but normal message.