* i8254:
  * ISR routine will free event objects if they couldn't be used.
  * disable()'s state machine will update such that re-enabling the IRQ
    works.

* SingleWaiterQueueC: Separated the constructor/initialize() methods from
  the function of setting a waiting thread. Now a separate function
  setWaitingThread() handles this.

* InterruptTrib: Silenced some IRQ context messages that filled up too much
  of the debug log.