Group thumbs by tag (only show each thumb once)
Group thumbnail sets under FIRST Tag in tagIds
Fix left indent/alignment within images/dataset
Don't show date-time stamps on Thumbnail Figure.
Check for 'Big' image before OME-TIFF creation. See #10761
merge develop -D org -I include -E exclude: PR 29 (Thumbnail fig tags develop)
merge develop -D org -I include -E exclude: PR 30 (OME-TIFF_Big_Images_10761_develop)