pydata/pandas — pull request #773 by yarikoptic (2012-02-10 18:48:53+00:00)
Title: unify API in regards to column-vs-columns

This is the "fix" only for 1 case out of few other possible:

```
$> git grep 'def.*column='
pandas/core/frame.py: def boxplot(self, column=None, by=None, ax=None, fontsize=None,
pandas/stats/misc.py:def percentileRank(frame, column=None, kind='mean'):
pandas/tools/plotting.py:def boxplot(data, column=None, by=None, ax=None, fontsize=None,
```