* Add code to test if any of the components in the schematic cache have been changed
  in the component libraries.
* Prompt user to accept or reject components when changes are found.
* If the user chooses to use the components in the cache, create a new library with the old
  components and add it to the beginning of the component library list so the schematic will
  not be changed.
* Create dialogs to handle user feedback and status.