make back end and front end theming configurable

I've seen some workaround for the button "save" or "cancel" problem with panels ipe but i don't think this is the right solution because bootstrap break the layout on the modals of panels ipe anyway. I don't known if it's panels ipe related or bootstrap so i will put this msg on both... but it would be great when you select another theme for administration, than panels ipe and maybe other ajax edit module would be rendered with admin theme and not with bootstrap theme.