New in version 0.13 for "Setting index metadata"
This section: http://pandas.pydata.org/pandas-docs/dev/indexing.html#setting-index-metadata-name-s-levels-labels makes no mention of "new in version 0.13". 

I believe that many of those methods were recently added.

For example on v12:

```
AttributeError: 'MultiIndex' object has no attribute 'set_names'
```
