Splits Session to GenericSession and ZebraSession where Generic supports any
search backend via the SearchEngine classes and Zebra maintains the direct
channel to the Zebra server.
Adds config files required for mapping BIB-1 attributes to Koha search fields
and SRU indexes to BIB-1 attributes.
Adds PODs.
Sponsored-by: National Library of Finland Signed-off-by: Stefan Berndtsson <stefan.berndtsson@ub.gu.se> Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>