Series repr issue (numpy.int64)
``` python
In [18]: df = pandas.DataFrame(np.random.randn(4,4))

In [19]: s = df.ix[3]

In [20]: type(s.name)
Out[20]: numpy.int64

In [21]: s
Out[21]: ---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
...
TypeError: 'numpy.int64' object is not iterable
```
