Validate UTF-8 before submitting text to CoreNLP
Remove commented out "INSERT INTO processed_stories" statement because this work is being done by the "mediawords_update_processed_stories.pl" script for some time now
Update script's formatting, add some debugging messages
Index CoreNLP annotations in MongoDB by stories_id because they will be requested using the stories_id later on
Add a convenience method annotate_stories_id()
Rename _corenlp_annotate() to _annotate_text(), annotate_*() to store_annotation_for_*() for simplicity
Remove usage of downloads_id because annotations are about stories and story sentences
On error, print the error message too
Introduce helper methods _encode_json() and _decode_json() because JSON module uses various parameters and it's easier to have them in a single place
Add subroutines to fetch story's annotation, story sentence's annotation and annotation of a story and all of its sentences
Print CoreNLP annotations in /admin/stories/view (for debugging purposes)