* Clean-up EntityManager a bit
- use tsl::robin_set instead of std::set (which should have been unordered::set
anyways).
- getListeners() now returns a vector which avoids to traverse a set twice.
Turns out that copying the set wasn't as efficient as I thought.
* Improve jobsystem a bit
We recently added a job reference counting mechanism, but we were a bit
too aggressive about taking/release references.
Also make the API more complete by adding explicit retain/release,
which is needed to allow several threads to wait on the same job.
Also improve futex code by inlining it.
bc3aee118a