Added model-checker tests for liveness, reachability and state limit

...ava/avatartranslator/modelchecker/AvatarModelChecker.java

...tartranslator/modelchecker/SpecificationReachability.java

src/main/java/cli/Action.java

ttool/src/test/java/cli/CLIAvatarModelCheckerTest.java

ttool/src/test/resources/cli/input/modelchecker_rl_expected

ttool/src/test/resources/cli/input/scriptmodelchecker_rl

ttool/src/test/resources/cli/input/scriptmodelchecker_sl