[Feature Request] toggle highlights on and off per page, without deleting them

[sgould420]

It would be nice to be able to turn off all of the highlights on a particular page, without deleting them.

When I highlight lots of stuff, I want to be able to turn the highlights off and view the original page, and then switch them back on. I don't want to delete the highlights and re-create them.

This would be particularly useful when you are not sure which highlights you created, or if some of them were already highlighted on the original page.