Pimplize SfxUndoActions.

Change-Id: I35ef457111f4cf8b811a4ee8bb676421746e1d9d
Pimplize SfxListUndoAction.

Change-Id: Ic82755788df237c455c802a039881a9d056f4df2
Forward-declare MarkedUndoAction.

Change-Id: I1c36077cada47bacfb8436cf3fb659e47d02da60