BibClassify: processing and output decoupling

* Decouples the output rendering from processing so that
  processing is re-done a second time when asking for a specific output
  format.

Tested-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Signed-off-by: Guillaume Lastecoueres <PX9e@gmx.fr>
BibClassify: dict output fix

* Improves wrong handling function of dict output.

* Adds better handling of corrupt caches.

Reviewed-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Signed-off-by: Georgios Papoutsakis <georgios.papoutsakis@cern.ch>