Lucene for OJS 3.4.0-0

Lucene plugin for OJS 3.4.0-x.

This plugin is not yet broadly tested and is expected to receive minor tweaks and fixes before it'll be production-ready. For that reason, I won't add it to the Plugin Gallery just yet. (This is the same as the current OJS 3.3.0-x compatible release.)

OJS 3.3 support

OJS 3.3 support - contribution from @asmecher