Bug 1042319 - [Gallery] Update gallery edit UI r=djf

I'm having trouble with the nomenclature here. is "edit mode view" the view with the save button or the view with the apply button? It isn't clear to me from the name.  What is the difference between "editor screen" and "edit mode screen".  I think maybe if you replaced "mode" with "tool" just about everywhere it might be clearer. Then you'd have hideEditToolView() and currentEditTool and edit-tools-apply-button and updateApplyToolButton().  I think that would make the code easier to understand.