Synchronization between instances

Lock free synchronisation of notifications across multiple instances of notification system (multiple readers/writers). Lock free implementation depends on atomicity of unlink(), RCU behavior of open file descriptors in Linux and fact that notification system only create, read or delete notifications. There are no updates, therefore no need for locks.

Notes:

• Sync will happen only on read operations (get, get_rendered, ...). There is no active sync (inotify or something like that), but it could be implemented later.