midiTable

-made the combo-box for MidiActions editable.
-Added a new column with a combo-box for the fresh parameter3 to the
Miditable.
ATTENTION: the combobox will only display categories,
so with this implementation the third parameter will not effectifely be
usable for other purposes.

Coding Style:
overloaded method
	insertNewRow(MidiAction *pAction, QString eventString, int eventParameter);
to avoid duplicated code in setupMidiTable