ENH: Read gpaw-output also for multiple k-points. Test included.

Closed username-removed-255251 requested to merge mwalter/ase:gpaw-io into master

I do not really understand how the test framework is set up in ase. The test included has to run gpaw to produce the output that is read later on. It needs about 5 seconds to run.

The automatic test using python -c "from ase.test import test; test(2)" skips the test and I do not understand how to change this behavior.