#40 Frequency axis labels in Spectrum Section plot at about 60kHz
When creating Spectrum Section plots with high sampling rate, the frequency axis (horizontal) has time format. It's still labelled in kHz and the very bottom of the pane seems to show the right frequencies, but the actual numbers on the frequency axis look like hours:minutes or minutes:seconds are very confusing.
As an example I created the file below using my PC 'arecord --device='hw:CARD=Intel,DEV=0' --channels=2 --rate=192000 --format=S32_LE --duration=4 tmp.wav && sox tmp.wav mono.wav remix 2 highpass 10000 && wavesurfer mono.wav'. The attached screensoft has the cursor over the 60kHz peak I expected to see and the bottom of the pane says 59992 Hz. However, the frequency axis says 0:59 kHz, and the next marking is 1:00 kHz.
I'm running 1.8.8p4-3ubuntu1 which comes with xubuntu 18.04.2 LTS
