Inconsistent API regarding table update

[SamJoan]

On table.py, on the EndpointTableModel class, the add() method does not refresh the table because of the issues I previously had with fireTableDataInserted after a clear() call when the table was sorted, where the insertion would happen at an offset which would trigger a KeyError in getEndpoint. See #9.

Now, clear(), update() and setFuzzed() all trigger the update of the table, but not add(). I think that all methods should be updated in such a way that they don't trigger the update for consistency, and we should make that the responsibility of the caller.