celery: msgpack serialization usage

* Changes default celery configuration to use msgpack instead of
  pickle and use rabbitmq instead of redis broker, after some
  problems under heavy load.

Tested-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
search: change union_update to union

* Due to changes in the behaviour of intbitset union_update function,
  union should be used if a return result is expected.

Reported-by: Kamil Neczaj <kamil.neczaj@cern.ch>
Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
base: Apache configuration template fix

* Fix newline issue when CFG_WEBSTYLE_HTTP_USE_COMPRESSION is missing.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
celery: make Redis default broker

* Makes Redis the default broker for Celery.

Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Acked-by: Jiri Kuncar <jiri.kuncar@cern.ch>
BibClassify: new API

* Adds a new API module for use by workflow tasks.

* Several updates and fixes to the module to improve output.

* Moves a function for easier future optimization,
  simplifying some operations.

Tested-by: Jan Aage Lavik <jan.age.lavik@cern.ch>