Fix unsafe SQL query in search suggestions controller.
Re #135: Create Log model to log messages to db.
Re #135: Show logged messages from db in admin log view.
Re #135: Remove RunCoCo.export_logger and RunCoCo.oai_logger
Re #149: Spawn background process to save new attachments to S3.
Re #149: Show status message in place of thumbnail while uploading file to S3.