Ok, I've found a way to "patch" this to work, although I don't know if this is the "correct" way to fix it, it does work for me. You need to edit 3 lines in 2 files:
1. Edit the "cache.py" file and change this line:
Line 800: with pricesFh or pricesPath.open('rU', encoding='utf-8') as pricesFh:
to this:
Line 800: with pricesFh or pricesPath.open('rU', encoding='utf-8', errors='replace') as pricesFh:
2. Edit the "plugins/maddavo_plug.py" file and change this line:
Line 608: line = line.decode(encoding="utf-8")
to this:
Line 608: line = line.decode(encoding="utf-8", errors="replace")
and change this line:
Line 611: line = line.decode(encoding="latin1")
to this:
Line 611: line = line.decode(encoding="latin1", errors="replace")
Then it should work now, at least it does for me now. Hopefully, @kfsone or @maddavo can fix this properly soon, but for now this seems to do the trick.
Hope it helps someone.