a fix to align scanned service frequencies to transponder.

[Hominidae]

I'd like to propose an improvement to the current
situation, where service frequencies from a scan go "raw" into the database.

I'd like to propose that the frequencies will get rounded to the corresponding
transponder frequency.

This will always enable the recording of channels on the same transponder with a single resource (tuner).
See my post about that problem here: viewtopic.php?f=52&t=4776&start=10#p31345