Store selection and active line in undo info and restore them on undo
Remove the added/removed items arguments from the selection changed signal

They're only used by one thing (the drag visual tool), so calculating
them is pointless overhead most of the time, and it simplifies the
visual tool code much less than it complicates the grid code.
Sort the actor and effect fields. Closes #1715.
Match the parser's section order when constructing files for undo