improved the way the translatable messages were stored!

The Output of my little test was disordered. every time I execute the test the order was different. Therefor I store the TranslatableMessage and the Occurence in a TreeSet and implemented Comparable there. 

In Addition a TranslatableMessage was stored more than one time if different classes used the same string. Now I doesn't attach the messages after a file was analysed successful, but I merge the messages and arrange that a message is just a single time in the catalogformatoutput