Printing a DataFrame is slow
For some reason, calling `print df` is really slow:

```
In [1]: import pandas

In [2]: import numpy as np

In [3]: df = pandas.DataFrame(np.random.randn(1000,100000))

In [4]: %timeit print df
1 loops, best of 3: 1.93 s per loop

In [5]: %timeit print df.values
1000 loops, best of 3: 1.25 ms per loop
```
