Bug 3301 - Speed up rebuild_zebra script

Bug 3301 - Speed up rebuild_zebra script

With this patch, rebuild_zebra can re-index a whole Koha DB
quickly:

  rebuild_zebra -r -b -nosanitize

Biblio (authority) records are dump directly in a file
from marcxml field without beeing transformed into
MARC::Record object and corrected.

DOCUMENTATION:

rebuild_zebra.pl new paramater:

-nosanitize  export biblio/authority records directly from DB marcxml
             field without sanitizing records. It speed up
             dump process but could fail if DB contains badly
             encoded records. Works now only with -x and -b

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>