Add option to hide index in pandas.Series.to_string
In the Dataframes.to_string function there is a option to not print the index:

index : bool, optional

```
whether to print index (row) labels, default True
```

Can this be added to the Series function to_string?

http://pandas.pydata.org/pandas-docs/version/0.17.0/generated/pandas.Series.to_string.html
