Adding association with arrow

src/main/java/ui/avatarcd/AvatarCDActorBox.java

src/main/java/ui/avatarcd/AvatarCDActorStickman.java

src/main/java/ui/avatarcd/AvatarCDAssociationConnector.java

...ain/java/ui/avatarcd/AvatarCDSpecializationConnector.java