fix #84
changed dkh_over_dkz
to dkz_over_dkh
in base.output.spatiotemporal_spectra.plot_kzkhomega
the calculations of the dispersion relation are now easier to understand
changed dkh_over_dkz
to dkz_over_dkh
in base.output.spatiotemporal_spectra.plot_kzkhomega
the calculations of the dispersion relation are now easier to understand