ice9-bluetooth defaults to hackrf

[ZeroChaos-]

Feel free to close this if you don't agree.

I feel the default of hackrf is less than ideal. I love the hackrf as much as the next person, but I would default to a more capable and likely radio like the bladerf. With a bladerf plugged in and no hackrf plugged in I get an avoidable error:

zero@theprophet ice9-bluetooth-sniffer % ice9-bluetooth -s -l -a                                                                                             (git)-[master] 
ice9-bluetooth: Invalid number of channels for HackRF, must be 20 or fewer

If at all possible, I feel the best user experience would be to automatically pick the most capable available radio, and then error if none are found. Keeping the existing ability for the user to select a radio, and "automagic default" makes more sense than simply defaulting to hackrf.

[jsmif]

TBH this threw me too on my first ever run of this tool too. I got the error "ice9-bluetooth: Unable to open HackRF: HackRF not found". So then I had to look at the --help, since the README.md didn't mention anything about specifying a device. (And when I looked at it, I then accidentally used the example command ice-bluetooth --extcap-interfaces as-is. It looks like the --help needs to be updated to use ice9 instead of ice. Made PR #16 )