In some cases modp_dtoa/modp_dtoa2 gives different precision then requested

```
Nick,

The code has the following branch:

    if (value > thres_max) {
        sprintf(str, "%e", neg ? -value : value);
        return;
    }

This is wrong as it ignores requested precision - sprintf uses 6 precision by 
default.
```

Original issue reported on code.google.com by `ilya.m...@gmail.com` on 10 Jun 2010 at 8:56
