DOC: IPython code blocks without In/Out prompts?
We currently use the ipython sphinx directive to run the code examples in our rst docs. This generates output like:

```
In [3]: s = pd.Series([1, 3, 5, np.nan, 6, 8])

In [4]: s
Out[4]: 
0    1.0
1    3.0
2    5.0
3    NaN
4    6.0
5    8.0
dtype: float64
```

(first code block from http://pandas.pydata.org/pandas-docs/stable/getting_started/10min.html)

This uses the `In []` and `Out []` that are characteristic for IPython. But, this also generates quite some "visual clutter" (certainly if the number gets bigger > 10 or > 100).

Assume this would be possible\*, what would people think about using plain python-style prompts? 
Something like (for the above example)

```
>>> s = pd.Series([1, 3, 5, np.nan, 6, 8])
>>> s 
0    1.0
1    3.0
2    5.0
3    NaN
4    6.0
5    8.0
dtype: float64
```

This has less visual clutter IMO (although many people are probably using ipython, so are familiar to the In/Out prompts)

\* the IPython sphinx directives allows to customize the input and output prompts, but this currently expects that a number is inserted into it. So the above will not work without adapting the ipython_directive.