SyncManager: When sending new Entities (both on client and server) make sure that parents are sent before children. This is crucial in keeping Entity parenting working during runtime when smaller id Entities are parented to bigger ids. Changed SceneSyncState to be a associative QHash that maps entities to EntitySyncState*, this makes for fast lookups when parents are needed inside the processing. Added EntitySyncState::weak to the Entity, we can get rid of scene queries being done all the time (I did not fully utilize this yet, should be added to be used in more of the SyncManager functions). Fixes #775.