Lerning to test

Now we learned how to test properly. There was a little difference that made the examples run if you installed oemof locally but not if you installed it from pypi.

We fixed that and skip 0.1.3 due to superstitions (1.3 is almost a 13). It is not true but a nice story 😏

Have a look at the 0.1.2 release to see the real changes.