Not all undo actions are atomic

[Laszlo Pandy]

Currently actions such as adding instruments and deleting instrument/events can be done in batch by selecting many instruments/event at once. However when undoing them each instrument/event is deleted or added separately. If something takes one click to do, it should take one click to undo.

Any action that can be done in batch must be changed to used the newly committed AtomicUndoAction class, so that everything in atomic from the users perspective.

[Laszlo Pandy (laszlok)]

Adding/deleting of instruments/events are now atomic. If you find something else that isn't but should be, drop me a mail.