Merge branch 'master' of gitlab.windenergy.dtu.dk:toolbox/WindEnergyToolbox

wetb/signal/tests/test_files/subset_mean_test.hdf5

wetb/signal/tests/test_first_order.py

wetb/signal/tests/test_fit.py

wetb/signal/tests/test_fouier_fit.py

wetb/signal/tests/test_spectrum.py

wetb/signal/tests/test_subset_mean.py

wetb/signal_tools/tests/test_first_order.py

wetb/utils/cluster_tools/cluster_resource.py

wetb/utils/cluster_tools/pbsjob.py

wetb/utils/cluster_tools/ssh_client.py

wetb/wind/air_density.py