manoelcampos/cloudsim-plus: BugFix and Small Improvements

Updates #130 Postpone DatacenterBroker shutdown to the end of the simulation when a termination time is set, instead of as soon as all cloudlets finish. This way, the broker waits for new Cloudlets and VMs submitted during simulation runtime, even if the broker is idle. Updates DatacenterBrokerSimple to request VM destroy during shutdown. In situations such as when a simulation termination time is set, the broker was kept alive to wait for new Cloudlets and VMs. However, this was causing VM destruction to be ignored when the broker was shutdown. Improves information printed by DatacenterBroker