Merge commit 'ee2ce6fa' into TEMPORARY_MERGE_PR_563

pySDC/helpers/spectral_helper.py

pySDC/implementations/problem_classes/RayleighBenard.py

pySDC/implementations/problem_classes/RayleighBenard3D.py

pySDC/implementations/problem_classes/generic_spectral.py

pySDC/tests/test_helpers/test_spectral_helper.py

...C/tests/test_helpers/test_spectral_helper_1d_chebychev.py

pySDC/tests/test_helpers/test_spectral_helper_1d_fft.py

...ts/test_helpers/test_spectral_helper_1d_ultraspherical.py

pySDC/tests/test_problems/test_RayleighBenard.py

pySDC/tests/test_problems/test_RayleighBenard3D.py