* Fall back to asynchronous events if IJobChangeListener timeout
detected (possible deadlock).

* Make sure all IJobChangeListener calls returned before a state change
happens to avoid stale Events to happen after the state change.

* Fix order of scheduled() and done() in case of reschedule:
Some IJobChangeListener like ProgressManager.createChangeListener()
expect a scheduled() to happen after done() even if a rescheduling
schedule() was called before done() happened.

* Fix cancel of InternalJobGroup (did synchronize wrong lock during
cancel events)

* avoid nested "synchronized (lock)"

* fix wake up of pool if Job does not end in worker thread #227

https://github.com/eclipse-platform/eclipse.platform/issues/193