Merge branch 'alessandro_branch' into 'master'

doc/avatarmodelchecker/images/modelcheckerwindow.jpg

doc/avatarmodelchecker/images/modelcheckerwindow.png

doc/avatarmodelchecker/ttool_avatarmodelchecker.tex

src/main/java/avatartranslator/AvatarActionAssignment.java

src/main/java/avatartranslator/AvatarActionOnSignal.java

src/main/java/avatartranslator/AvatarBlock.java

...main/java/avatartranslator/AvatarExpressionAttribute.java

.../avatartranslator/AvatarExpressionAttributeInterface.java

src/main/java/avatartranslator/AvatarExpressionConstant.java

src/main/java/avatartranslator/AvatarExpressionSolver.java

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

...in/java/avatartranslator/modelchecker/SafetyProperty.java

...ava/avatartranslator/modelchecker/SpecificationBlock.java

src/main/java/cli/Action.java

src/main/java/ui/AvatarDesignPanelTranslator.java

src/main/java/ui/window/JDialogAvatarModelChecker.java

.../src/test/java/avatartranslator/AvatarExpressionTest.java

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

ttool/src/test/resources/cli/input/scriptmodelchecker_val4

.../test/resources/cli/models/CoffeeMachine_Avatar_Async.xml