removed a way to operate with the transactions in a double hash table method.
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the transactions could be stored in the following manner:
TRANSACTION_IDs --> ITEMS_BUCKET --> UNIQUE_ITEMS
it is a fast method, however not suggested in the apriori algorithm,
it was possible to add elements without the need to check for duplicates. using ontologies might be faster as it doesn't need to sort data (it print sorted, though)
removed comments; organized code
moved the support count to a more understandable fashion