add axis argument to unstack
I occasionally find myself wanting to unstack on the columns rather than index, a workaround is to do it on the transpose and then transpose again:

```
frame =  pd.DataFrame({
    'home'    : ['CHI', 'ATL', 'SEA', 'DET', 'STL','HOU' ,'CHI','CHI'],
    'away'    : ['DET', 'CHI', 'HOU', 'TOR', 'DAL', 'STL', 'MIA', 'SEA'],
    'awayPTS' : [88, 75, 105, 99, 110, 85, 95, 100],
    'homePTS' : [92, 88, 95, 97, 100, 74, 98, 110],
})
frame.columns=[['away', 'away', 'home', 'home'], ['team', 'PTS', 'team', 'PTS']]

In [11]: frame.T.unstack(0).T
Out[11]: 
        PTS team
0 away   88  DET
  home   92  CHI
1 away   75  CHI
  home   88  ATL
2 away  105  HOU
  home   95  SEA
3 away   99  TOR
  home   97  DET
4 away  110  DAL
  home  100  STL
5 away   85  STL
  home   74  HOU
6 away   95  MIA
  home   98  CHI
7 away  100  SEA
  home  110  CHI
```

Annoying thing is that this will change the dtypes (because the transpose has mixed dtype).

```
In [12]: frame.T.unstack(0).T.dtypes
Out[12]: 
PTS     object
team    object
dtype: object
```

_see this [SO answer](http://stackoverflow.com/a/18429210/1240268)_
