Weird error in master when asked for type(df)
``` python
In [9]: type(detectors)
WARNING: Exception in text/html formatter: unbound method _repr_html_() must be called with DataFrame instance as first argument (got nothing instead)
Out[9]:
pandas.core.frame.DataFrame
In [10]: detectors.info()
<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 1565757 entries, 2008-01-08 17:15:29.111000 to 2008-01-18 07:57:01.504000
Data columns (total 4 columns):
a6_11    1565757  non-null values
b1_11    1565757  non-null values
b2_11    1565757  non-null values
b3_11    1565757  non-null values
dtypes: int64(4)
In [11]: 
pd.__version__
Out[11]:
'0.13.0rc1-59-g90990db'
```

I noticed another oddity: Why does the type-display create an output numbering (=Out[9]) but the display of detectors.info() does not? Something to do with IPython?
