AUP3: Reduce crash exposure when compacting

There's still the possibility if a crash happens at just the
right time that the project will be named "<project>_compact_back"
so we should probably look for it during startup.

This also changes all "Vacuum" references to "compact".

src/menus/FileMenus.cpp

@@ -183,7 +183,7 @@ void OnCompact(const CommandContext &context)
       currentTracks->Add(t->Duplicate());
    }
 
-   projectFileIO.Vacuum(currentTracks, true);
+   projectFileIO.Compact(currentTracks, true);
 
    auto after = wxFileName(projectFileIO.GetFileName()).GetSize() +
                 wxFileName(projectFileIO.GetFileName() + wxT("-wal")).GetSize();