for(var x in array) is broken with this pollyfill.

The current method of attaching the find function causes all arrays to seem to have an extra item when using for(var x in y).

e.g. the following is run in the IE console shown with the output :
``` 
f=[1,2,3,4]
> [object Array] [1, 2, 3, 4]

for(var x in f){console.log(x)}
> 0
> 1
> 2
> 3
> find

```

I have a fix which I'll be sending on a pull request.