#1640: Handle biblio fields. Handle multiple usages of file in text field.
#1640: add image fields to list of field types to check
#1640: Set count for biblio nodes.
#1640: Rewrite file usage finding function to take a node instead of a file.
#1640: Saving progress.
#1640: Handle case where a node has no space.
#1640: Increase limit. Adjust delete conditions.
#1640: Rearrange how spaces are handled.
#1640: Check file exists.
Merge Scholar-3.x
#1640: Delete file_usage records for nonexistent nodes, and files that are not through imagefield_crop.
#1640: Bug fixes to the file finder function.
#1640: Weirdness with escaped strings in sql queries. Remove debugging lines.
Merge branch 'SCHOLAR-3.x' into 1640-reviving_file_usage_update
Merge pull request #3912 from openscholar/1640-reviving_file_usage_update

1640 reviving file usage update