Preserve non-editable elements when applying list.
Selected non-editable element cannot be a block limit or splittable block.
Made my life easier - added some sense to the weird code.
Bookmarks need to be kept next to block contents in case of non-editable block selection.
If bookmark has no neighbour, don't except it.
Removed unused variable.
Don't autoparagraph content if selection is anchored in non-editable element.
Don't give element#isBlockBoundary a reason to stop on drag handler, which wasn't positioned, but was a block.
Never consider read-only element as a div limit.
Never consider read-only divs in getSurroundingDiv.
Never consider children of non-editable element when creating divs.