Add a column/indicator for sequences that have image/category/groups assigned.

[kevinsaucier]

It would be nice if there was some indicator in the grid of sequences that would show when 'additional' information has been added to a sequence (kind of how the Display Name is shown). I add 'New for ' images and it's hard to know which has it added until it's active and I check the viewer page. Same with categories, groups, and maybe Artist.