[Cin] Backups discussion

[Andrew Randrianasulu]

So, right now CinGG tracks your work and can create two backup files
(backup.xml and backup.prev). It works [hopefully] but feels a bit TOO dangerous in 
the event of crash, when confused user may save backup instead of loading it.

Recently I crashed Audacity a bit :}
It surely shows up Session recovery dialog, where you can see backups with time-date added
to their names, and choose one to load.

Do you think similar system will work for CinGG?

At very minimum I think I can try to write 'we_are_running.lock' file on app startup,
and only delete it on clean shutdown. So, there will be way to act in case we detect crash.

After we detect crash - probably right now Warning can be displayed, 
instructing user to seek LOADING backups.

If I can made this sytem work reliably - I hope multi-backup solution also will be within reach.