Add ordinal suffix

```
module.exports = function ordinal(num) {
var suffix=["th","st","nd","rd"],
val=num%100;
return num+(suffix[(val-20)%10]||suffix[val]||suffix[0]);
};

_.ordinal(1) // 1st
_.ordinal(2) // 2nd
_.ordinal(3) // 3rd
_.ordinal(4) // 4th
```