Move download storage tests to a separate directory so they don’t mix up with the rest of the unit tests
Pass $db parameter to fetch_content(), remove_content() and content_exists() too in order to unify the interface to download storage methods
Merge branch 'master' into store_downloads_in_postgres
* Added a way to store raw downloads directly in PostgreSQL database, "raw_downloads" table
* Set storing downloads directly in PostgreSQL as the default storage method because it is expected that most 3rd party deployments won't be huge so creating files under data/content/ doesn't make sense
Merge branch 'store_downloads_in_postgres' into optimize_extractor