Bug in simulation finished code.

[alexronquillo]

With the arrivalPeriod close to the simulationPeriod, the threads are still running by the time the simulationPeriod ends.

Input values:
simulationPeriod = 1.0
arrivalPeriod = .75

Optimal Airport Simulation
Simulation has completed. Results Follow:
Average Gate Utilization: 0.81972
Average Bay Utilization: 0.5227
Average Wait Time: 0.10827433628318581
Rejected planes: 246
Planes Serviced: 226
Average Sojourn Time: 0.0
Average Runway Utilization: 0.35000000000000037

Plane 474 took off. Time: 1.021
Air Traffic Controller signals Plane 194 to land. Time: 1.021
Plane 194 starts landing procedure. Time: 1.022
Plane 199 finishes receiving service at Gate 6. Time: 1.022
Plane 199 added to the departure queue.
Gate 6 starts cleaning procedure. Time: 1.022
Gate 6 is available. Time: 1.022
Air Traffic Controller signals Plane 249 to takeoff. Time: 1.022
Plane 249 starts takeoff procedure. Time: 1.022
total wait time of Plane 249: 0.564
Sojourn time of Plane 249: 0.0
Air Traffic Controller signals Plane 413 to land. Time: 1.022
Plane 413 starts landing procedure. Time: 1.022
Ground Movement Controller assigns Plane 194 to Gate 6.
Plane 194 landed. Time: 1.025
Plane 488 took off. Time: 1.025
Plane 194 starts receiving service at Gate 6. Time: 1.025
Air Traffic Controller signals Plane 199 to takeoff. Time: 1.025
Plane 199 starts takeoff procedure. Time: 1.025
total wait time of Plane 199: 0.6339999999999999
Sojourn time of Plane 199: 0.0
Air Traffic Controller signals Plane 412 to land. Time: 1.025
Plane 412 starts landing procedure. Time: 1.025
Plane 249 took off. Time: 1.026
Air Traffic Controller signals Plane 62 to land. Time: 1.026
Plane 62 starts landing procedure. Time: 1.026