DataFrame.to_records failure with DatetimeIndex
http://stackoverflow.com/questions/11754334/dataframe-to-records-gives-an-error-when-typeindex-is-datetimeindex

```
In [20]: df = read_clipboard(sep='\s+', parse_dates=True)

In [21]: df
Out[21]: 
                   a         b         c
2012-08-01  2.355928 -2.465061  0.240094
2012-08-02 -0.952323  0.746623 -0.384021
2012-08-03  1.460156  0.292560 -0.494793
2012-08-04 -0.989584 -1.630384  1.373587
2012-08-05  0.014760 -0.789603 -0.622780

In [22]: df.to_records()
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-22-6d3142e97d2d> in <module>()
----> 1 df.to_records()

/Users/wesm/code/pandas/pandas/core/frame.pyc in to_records(self, index)
    889             names = list(map(str, self.columns))
    890 
--> 891         return np.rec.fromarrays(arrays, names=names)
    892 
    893     @classmethod

/Library/Frameworks/EPD64.framework/Versions/7.1/lib/python2.7/site-packages/numpy/core/records.pyc in fromarrays(arrayList, dtype, shape, formats, names, titles, aligned, byteorder)
    546     # Determine shape from data-type.
    547     if len(descr) != len(arrayList):
--> 548         raise ValueError, "mismatch between the number of fields "\
    549               "and the number of arrays"
    550 

ValueError: mismatch between the number of fields and the number of arrays
```
