Add Button to Restore Default Settings

[cwitkowitz]

Currently, settings are stored in a .settings file, accessible through the general tab of the settings window. If a user uninstalls HARP, we may want to have a way to remove this file so it doesn't track settings across different installations of HARP. At the very least, we could add a method to restore the default settings (i.e., delete this file).

[cwitkowitz]

There should also be a simple way to clear the logs. I'm not sure if it should be combined with resetting the settings.