Bug 1042319 - [Gallery] WIP patch of update gallery edit UI and visuals

To clarify, if you have all the state in a single object, then you can make a copy of the object before entering an edit mode, and if the user cancels, then just revert to the copy.  And, rather than restoring the UI of the edit modes when the user cancels out of it, you can just ensure that setEditTool() always initializes the UI for each edit mode to the current state.