Change channel scanning upper limit for US and Canada

[jwittkoski]

This issue is based on a post in the SageTV forums:

https://forums.sagetv.com/forums/showthread.php?p=626292#post626292

"Can we get the tuner channel scan amended so it searches range 2- 36 as per new standard rather than 2 - 69? Where I am in Canada they are already relocating channels down the band to accommodate the re-purposed frequencies to cellphone use etc. This would lower the time & stress factor when having to redo setups. I don't know when the newer standard arrives in USA. Maybe it is different there since they are adopting atsc 3.0?"

[jwittkoski]

Suggestion was also made that the upper limit could be configured in the properties file.