sincos-test fails because numpy is not available on buildbot
Bug report
The test_ff_navierstokes_sincos fails (only!) on buildbot
What happened / Problem description:
The convergencetest.py includes numpy, but numpy is not available on buildbot. We should try to get rid of numpy in this case. I did not look into the files yet, but the other convergence tests do not need numpy and were desigend to work without numpy.
According to @timok installing numpy on buildbot is not wanted because it is quite large.
Environment:
- Dune version: master
- DuMux version: master
- Others: gcc, Python version: 2.7.9