Feature request: Display only the currently-active VFO

[bracklanna]

If possible, please add an option to display only the active VFO on the screen. For scanner use it is confusing to see the A and B VFOs at the same time.

See also this issue in the main ezgumer fork:
egzumer/uv-k5-firmware-custom#124

By the way, Thank you for adding the "start scanning on power-up" feature, it's great.