Squashed commit messages :
Draft.

Draft 2.

Draft 3.

Deadlock.

Lock worker lock and compute engine lock in the same order everywhere.

Forward SpRuntime nbThreads argument to SpComputeEngine constructor. Remove debug printouts.

Lock all locks in scoped ordered lock through a unique_lock instance.

Implement svg trace function in SpTaskGraph. Implement stopAllThreads function in SpRuntime. Use plain mutexes in SpScopedOrderedLock.

Allow compute engine pointer of worker to be changed by main thread.

Remove unnecessary boolean variable.

Optimize for the case where workers just keep popping the next task from the same compute engine.

Begin work on detachWorkers function.

Begin remodeling code to allow workers to be detached.

Deadlock.

Working version.

Remove unnecessary shouldBeMigrated member variable.

Properly stop workers and compute engine.

Fix broken svg trace generation function.

Remove unused classes.

Add compute engine and task graph unit tests. Fix avaiable workers logic.

Use small_vector in compute engine.

Refactor compute engine unit test.

Remove redundant synchronization.

Forgot to add lock back into bindTo function.

Trying to add atomics for most common case (broken).

Seems to work.

Bind to ce should be release/acquire.

Stop flag memroy operations should be memory order relaxed. Load of ce inside mutex protected region should be relaxed. Add comment explaining choice of memory order for atomic load of ce in worker loop.

Set thread id in worker constructor.

Change comment about ce load memory order.

Condition inside waitOnCe was wrong.

Forgot to remove duplicate code. Change update logic for waiting worker counters.