Renum node numbers.

[fcmartins]

Node numbers are not being renumbered correctly. Use a graph visitor for renumbering them well.

Example:

public void nextedFors () {
    int soma = 0;
    for (int i = 0; i < 10; i++)   // Rui: podíamos simplificar estes nós...
        for (int j = 0; j < 10; j++)  
            soma = i + j;
    System.out.println(soma);       
}

Node 5 should be 3, for instance.

[ruigameiro]

Visitor updated.