* Make scene functions return array instead of mutate array
- Not all functions were changes; so the given argument was a new array to some
* Make data restoration functions immutable
- Make mutations in App component
* Make history actions immutable
* Fix an issue in change property that was causing elements to be removed
* mark elements params as readonly & remove unnecessary copying
* Make `clearSelection` return a new array
* Perform Id comparisons instead of reference comparisons in onDoubleClick
* Allow deselecting items with SHIFT key
- Refactor hit detection code
* Fix a bug in element selection and revert drag functionality
Co-authored-by: David Luzar <luzar.david@gmail.com>
* Remove `generatedraw` from element object
- Create a function that renders a single element
- Refactor rendering selected elements
* Replace getElementAbsoluteXY with getElementAbsoluteCoords
* Extract History into its own module
* Encapsulate undo and redo actions within history
* Encapsulate clearing redo stack within History
* Add private access modifiers to scene history class member variables
* Remove duplicate files
