Move examples to sphinx gallery?

[mfeurer]

sphinx gallery provides a easy way to render examples in a sphinx documentation. Most important, it does not rely on line numbers as our current examples do and would be less brittle.

[mfeurer]

We should also start unit-testing our examples to avoid issues like #389 .

[mfeurer]

The examples are ported to sphinx gallery, we still need to port the actual documentation.

[mfeurer]

Based on PR #697 we should also integrate them with mybinder.

[KEggensperger]

@mfeurer Can I close this? I created a new issue for adding Binder support.