GUI changes ----------- Configuration changes made in the bitcoin GUI (such as the pruning setting, proxy settings, UPNP preferences) are now saved to `/settings.json` file rather than to the Qt settings backend (windows registry or unix desktop config files), so these settings will now apply to bitcoind, instead of being ignored. Also, the interaction between GUI settings and `bitcoin.conf` settings is simplified. Settings from `bitcoin.conf` are now displayed normally in the GUI settings dialog, instead of in a separate warning message ("Options set in this dialog are overridden by the configuration file: -setting=value"). And these settings can now be edited because `settings.json` values take precedence over `bitcoin.conf` values.