OpenILS::WWW::AddedContent now supports fetching content by record ID.
To start, this lets us request content in a way that uses both ISBN
and UPC as keys, assuming the AC handler and provider support it.
The previous method of requesting AC data continues to be
supported, and should be unaffected.
Business::ISBN is used to clean ISBN values when fetching by record ID
If we find no valid ISBN and no UPC values in the record,
do not attempt to call an AC handler. This will need
to change when we have AC handlers that rely on other
possible keys.
Attempt to serve from cache before fetching keys from the bib
record in the database.
Signed-off-by: Jeff Godin <jgodin@tadl.org> Signed-off-by: Ben Shum <bshum@biblio.org>