Querki should have a mechanism for contextual help

Summary: We need to have some way for users to ask, "What the heck is that?"

Ideally, this would be by a context menu item, but you can't enhance the context menu via Javascript in anything but Firefox. So if we go that way, we would have to go whole-hog: override right-click / long-press and build our own context menu system. That shouldn't be done lightly.

Another possibility would be a draggable question mark: drag over something, and it becomes a context-help request. But how would we deal with menu items?