Future deprecation in the pandas library when using rule_from_table

This is the warning message:

```
..\fuzzylogic\classes.py:468: FutureWarning: The 'delim_whitespace' keyword in pd.read_table is deprecated and will be removed in a future version. Use `sep='\s+'` instead
  df = pd.read_table(io.StringIO(table), delim_whitespace=True)
```

Still working, just to prevent