Adding Tasks in the Future

[MBaczun]

Simulations should have the ability to add Tasks that will start at some point in the future to the Coordinator.
This would allow the inclusion special events like scheduled maintenance to our simulations.

The simulation should:

• be able to add tasks that start at a future time
• be able to remove/edit future tasks

The coordinator should:

• track when to start a future task (possibly with a new CEvent)
• store and start a future task when the time comes OR ask the simulation for the task once the time has come.

Some of the possible challenges associated with this have already been discussed in #18, where we consider the difficulties of maintaining future tasks in the CEvent priority queue.

[PetrosPapapa]

It would be much better to add an extra earliestStart field in Task rather than use the CEvent queue. The Scheduler will then take care of the start of the task, like it already does for any other task.