- Added recent files setting.  Currently app does not utilize the setting.
- Also fixed bug where autosave settings were not persisted on Save().
Renamed field.
Added header.
If recent files already contains a given file, promote it to the top instead of adding it twice.
Updated copyright year.
Raise an event when an open diagram is closed.
Record closed diagrams in recent files.
Added file header.
Added collection mirror.
Added recent files menu to the UI.
Removed some of the padding above and below menu separators.