Initial pass at smaller, three-across document panels
Don’t transfer props; just pass them.
Merge origin/master

Merge remote-tracking branch 'origin/master' into 477-protocol-docs
Some experimental changes to Document processing to indicate popover state to parent objects.
Restore some lost changes
Merge with origin/master
New model for popovers, pushed up to App.js, and using React context.
First pass at making generic popover content rendering
Center and scale preview icons in image container
Now ignore clicks in popover bubble
Dataset entries now use the compact document display.
Moved popover styles to new SCSS file, some cleanup, and fix FF incompatibility.
First pass at lightbox function for images
Finish lightbox for image documents; handle ESC to dismiss lightbox
Merge in origin/master
Small graphics fix-ups
Merge in origin/master
Cleaning up styles; will continue
Styling and ARIA tweaks, and cross-browser fixes
Merge in origin/master