+ it does not require loleaflet and loolwsd, because
loolwsd server can run on a separate machine, and
loleaflet will be served by loolwsd in the near
future.
+ it requires php5-apcu and the following line should be
inserted to owncloud/config/config.php:
'memcache.local' => '\OC\Memcache\APCu',