Adding contant value in Avatar: handling random, method call and receive message

modeling/AVATAR/PressureController.xml

src/main/java/avatartranslator/AvatarBlock.java

src/main/java/avatartranslator/AvatarSyntaxChecker.java

src/main/java/ui/AvatarDesignPanelTranslator.java

src/main/java/ui/avatarbd/AvatarBDPanel.java