Example Notebooks Update

[maxsiska]

The example notebooks and the documentation are not up to date.
We should make some changes to ensure that the code runs as advertised.

[michaelosthege]

In #61 I'm re-running at least some of the notebooks.

To solve this issue we should adop this configuration:

https://github.com/pymc-devs/pymc/blob/23a163663c52a11cf9985c698d4112291a0a7acb/docs/source/conf.py#L149-L153