Bump version to 3.6

Fix parsing of trainz-build stored as int.

Fix parsing of kuid2 without version

Add ability to choose export filename

- Add settings window
- Add export filename options
- Add overwrite policy
- Store settings and retrive them on application restart
- Fix Trainz build format localization in main gridview
- Show modal dialogs centered on main window
- Bump copyright to 2020
- Bump version to 3.3

Bump version to 3.1