Simulation event scheduling and dispatching engine

The simulation engine consists of two primary classes and their derivations: a Simulation singleton class that controls the execution of the simulation, and an abstract Event class that represents individual events and their actions. (The EventQueue class mentioned in the original specification has been deferred.)

Events can be scheduled, and then subsequently get dispatched, but they currently cannot be descheduled or rescheduled. Events are dispatched in order of their due time and priority.