Session restore does not inform user

1. Make sure auto save is turned on
2. Work on a score without manually saving the file
3. After at least two minutes force quit MuseScore to simulate a crash (on Windows you can do this from the task manager)
4. Restart MuseScore

Expected behavior: MuseScore informs the user that the score they are looking at is an auto-saved version of the file, not the manually saved version.

Actual behavior: MuseScore opens the auto-saved score with no notification.

Discussion: Most of the time the user will want the auto-saved version since it contains the most recent of their work. After a crash I occasionally want the manually saved version. It is important for the user to understand that they are looking at an auto-saved version and that the manually save version still exists. Take a look at the session restore in Microsoft Word and other document-based applications for some ideas.