A "file has changed" star + skipping confirmation dialogs

[Chordian]

trafficstars

Whenever a data has been changed in a file after loading or starting from scratch, a star is added in the window title bar. Apart from being able to see that you have made changes, it also affects many confirmation dialogs.

If nothing has been changed since load or start, the confirmation dialog for new load, quit program, etc. are not shown.

[Chordian]

This is a task migrated from workstreams in Slack.