Add ThreeStepCycling scheduler + fix minor bugs/mistakes

src/example/philosophes/MainPhilosophe.java

src/example/philosophes/Philosopher.java

src/example/randomants/MainAnt.java

src/mas/implementation/schedulers/AsyncCycling.java

src/mas/implementation/schedulers/FairCycling.java

src/mas/implementation/schedulers/FairPosCycling.java

...implementation/schedulers/PausableThreadPoolExecutor.java

...mplementation/schedulers/variations/ThreeStepCycling.java

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

src/mas/ui/SchedulerToolbar.java