API for post-processing

[zuckerruebe]

As a user I'd like to be able to post-process simulation data using a simple, well documented Python API. The API should be simple, so that novice users can do everything they can currently do using .config files without knowing barely any Python at all. At the same time, the API will be much more flexible for users who know some Python.

Design ideas
Two parts/layers:

1. Data loading
2. Plotting