Bug 13264: Make opac_utf8.t launch its own helper processes

Bug 13264: Make opac_utf8.t launch its own helper processes

This patch makes opac_utf8.t launch its own:
- zebrasrv process
- rebuild_zebra.pl (daemon mode)

It also takes care of killing them when finished. It sets a frecquency
of 5 seconds for the indexer, and waits 10 just in case before looking
for the indexed records.

To test:
- Just launch the tests.

Edit: fixes on the license text.

Regards
Tomas

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
(cherry picked from commit 5e43f20a448f86915e64e18d6dccbb6e9ced4be6)
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>