IsNumeric is declared without checking if it is already defined or not... which conflicts with my code

**IsNumeric** is declared without checking if it is already defined or not... which conflicts with my code and I can't remove my one from the gamemode since the args differ from YSI's

```
error 025: function heading differs from prototype
error 021: symbol already defined: "IsNumeric"
fatal error 107: too many error messages on one line
```