Derived version of QUndoStack
Add undo/redo to edit menu
First undocommand is for move
Updating how pointers are swapped in UndoStack
Undo/redo now works for inspector moving
Set text in UndoMoveCommand
Switch to stack-aware QUndoCommand derivative

This will be necessary for upcoming pointer-wrangling.
Undo/redo for adding link
Can't use QPointers, as they'll NULL themselves
Properly connect connections on deserialization
Working on UndoAddLinkCommand integration
Don't call checkDragTarget if already connected
Make undo work for link deletion
Adding command to change datum expression
Change terminology in UndoMoveCommand
Clean up EventFilter in Inspector text
Script editor undo/redo
Magic to keep cursor position in ScriptEditor undo/redo
Remove superfluous newline
Set up undo/redo in DatumTextItem