+Options)Load local settings from File. Succeeds if File
does not exist, setting the default save-file to File. Options
- Define how to handle settings that are not defined. When
error, an error is printed and the setting is ignored. when
the setting is loaded anyway, waiting for a definition.
If possibly changed settings need to be persistent, the application
must call save_settings/0
as part of its shutdown. In simple cases calling