This details how to use both a HackRF One and RTL-SDR Blog v4 on a
RaspberryPi.

This is based on secplus_reader.py, but strips away all the QT Gui and
just operates as a local CLI application, printing the detected results
to the console.

There is some minor re-organization of the Connections to make it more
readable, and hard-coding of the frequency appropriate for my use case.

This sets up a baseline to be able to have one door, opened by one
rolling code opener, that must present a code in the right range.  I
have only tested it with a Security 1.0 opener so far, and it does not
yet have code for actually opening a door via any mechanism.