Move tests to the pytest framework.

[yakutovicha]

fixes #28
fixes #29
fixes #31

[yakutovicha]

@ltalirz do you have an idea why the 0907397 tests are failing?

The problem is with example_base_binary_restart.py If I run it without pytest, it goes fine, but under pytest it is hanging.

[ltalirz]

I would have to look through the code...
If you can reproduce it locally, it should be quite straightforward to figure out which part is hanging.

[yakutovicha]

I would have to look through the code...
If you can reproduce it locally, it should be quite straightforward to figure out which part is hanging.

Yes, locally I have the same problem. But I don't know what to look at to understand the origin of the strange behaviour.

Looks like the calculation wasn't submitted and top doesn't show anything strange.

What should I look at to narrow down the origin of the problem?

[yakutovicha]

I am going to merge this PR to make a release. The issue of the hanging test I will solve in a different PR.