Add simple filter for already seens. If none, fall back to original array (#3618)
Add simple filter for already seens. If none, fall back to original array (#3618)


jelliotartz/Panoptes-Front-End,amyrebecca/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,amyrebecca/Panoptes-Front-End,jelliotartz/Panoptes-Front-End,zooniverse/Panoptes-Front-End,amyrebecca/Panoptes-Front-End