Batch

- completed the UI for issue #17
- moved "pitch mod min/max" and "seed" to the "global" tab
- remade the midi generator (polyNote) and step drivers to accommodate
changes relative to issue #17
(see usermanual : "UI — tab correspondence")
- implemented Live Parameter Step
- minor changes (GUI, manual, etc...)

STILL TO DO:
adapt the flam (or delay) functions of the MIDI generator to issue #17