Feature: exclude/include frequency range

[jedi7]

Hi,

it will be nice if will be possible to exclude frequency ranges (defined by user) in which is not interested. For example user wants listen only to amateurs radios, but they are divided into multiple freq ranges. So user will define which ranges (between these amateur freq ranges) do not want to see.

It can be then used also for scanning, where we do not need to scan whole area, but only interesting freq. ranges.

Maybe will make sense to make also (or only) "include frequency range", where everything will be disabled and user will enable only specific ranges.