0) Mirar las APIs de las 6 collections

1) https://docs.oracle.com/javase/7/docs/api/java/util/Collections.html
Collections no solo tiene sort(collection).
Mirate:
min(collection)
max(collection)
shuffle(list)
reverse(list)
disjoint(collection, collection)
swap(list, int, int)
(todos los metodos de la class son static)

2) http://stackoverflow.com/questions/10750791/what-is-the-sense-of-final-arraylist
Llegir per veure que passa si declarem com a final una collection

3) Cambiar Ficha para que use toStringForComparable()

4) Get a spreedsheet.
Convert it to CSV
Generate a class that represents a row
Implement the toStringForComparable() in such a way that the ordering
    is (for instance) first for second column, then for first, then for third.
And, that reads the CSV file and writes another one sorted.

