Adding message loss to asynchronous channels

src/avatartranslator/AvatarRelation.java

src/avatartranslator/AvatarSpecification.java

...tartranslator/directsimulation/AvatarSimulationBlock.java

.../directsimulation/AvatarSimulationPendingTransaction.java

...nslator/directsimulation/AvatarSimulationTransaction.java

...lator/directsimulation/AvatarSpecificationSimulation.java

src/avatartranslator/touppaal/AVATAR2UPPAAL.java

...ctivesimulation/AvatarSpecificationSimulationSDPanel.java