Now you can run $PREFIX/bin/rfmonitor (which setup.py creates for you),
or pretty much equivalently, python -m monitor.app .

The configdir substring has changed to etc/rfmonitor; monitor alone is
too generic.  We now prioritize config file locations, and try to figure
out if /usr/local/etc or /etc should be the system prefix.  We
prioritize ~/.local/etc if it exists.