translate the most-used features of my too-big-for-bash script into python3,
which is clearly much better suited. Tried to keep the structure and variable
names intact so that diff has a chance of showing something, but when a class
replaces a bunch of arrays that were being kept in sync there's only so much
you can to. Currently doesn't support stuff like app upgrades and switching
from tcp to udp, but those should be relatively easy to bring over from the
.sh when/if I need them.
