minor refactor to use callback selectItems

minor fixes
Merge pull request #809 from proquest/ovid-callback
minor refactor to use callback selectItems
[beck-online] Fix decisionType logic
Broken in 23add2a168c38f45d15f62bfb77e1668b83670ab
Thanks @rm2342
[OVID Tagged] Small hack to pick up OVID item IDs for current session
Hackish, but the benefits are great, since this is now being used by Ovid web translator
Couple minor fixes.
[Ovid] Almost a complete rewrite
Use OVID Tagged translator for imports
Attach PDFs where available
Needs some more testing, but works pretty much everywhere, except for PDF view pages _if_ they were accessed from the individual item page and not from search results. Doesn't appear to be possible to reconstruct metadata POST parameters that way. Might consider going to a different page in those cases to fetch metadata.