This should fix the warning message:
"Attribute Qt::AA_EnableHighDpiScaling must be set before
QCoreApplication is created."
Which should fix the small fonts reported by some users.
We may also need AA_UseHighDpiPixmaps.
Originally UI config file was saved to ~/.opensnitch/ui-config.json
Now those values are saved to ~/.config/opensnitch/settings.conf, along
with new ones.
Closes#3