Add isFinished() and waitUntilFinish() in Schedulable interface

src/example/philosophes/MainPhilosophe.java

src/example/philosophes/Philosopher.java

src/mas/core/Schedulable.java

src/mas/implementation/schedulers/AsyncCycling.java

src/mas/implementation/schedulers/FairCycling.java

src/mas/implementation/schedulers/FairPosCycling.java

...mas/implementation/schedulers/variations/TwoDCycling.java