code: public StateMachine<S, T> addTransition(T newTransition, S fromState, S toState){
  		definition.addTransition(newTransition, fromState, toState);
  		return this;
  	}
docs: Add a transition to the state machine. Transition from a state to itself is allowed.
  @param newTransition	the transition to be added, must not be null.
  @param fromState		from state of the transition, must have been defined already
  @param toState		to state of the transition, must have been defined already