Implement the LFO1 and LFO2 effects.

For now, this is just for rp355, though the code should work for other
devices with minimal modification.

1) The EffectValues for values_*_assign need to be VALUE_TYPE_POSID.

2) Disabmiguate "Delay Tape" for a couple of EffectSettings. This fixed
   some bugs in the creation of the global modifier group.

3) Remove #if 0's around the definition of the lfo2_settings.

4) Define proper lfo1 and lfo2 groups arrays.

5) Define the lfo2_effect[] array.

6) Add the lfo1 and lfo2 effects to the rp355_effects array.

7) Disambiguate "EQ B" from "Eq" for some effedts in the modifiers array.

8) In push_message(), after we receive the RECEIVE_MODIFIER_LINKABLE_LIST
   message, kick off the creation of the EXP, LFO1, and LFO2 effects.

9) Generalize the function used for the pedal1_assign effect and make it work
   for lfo1 and lfo2 as well. Convert printf's to debug_msg().

10) Since we're destroying the association of the grid with the placeholder
    combo box entry, steal the data so the child widget isn't destroyed.

11) Silence warning on exit about 0 unread messages in queue.

gui.h

@@ -29,6 +29,6 @@ void gui_create(Device *device);
 void gui_free();
 gboolean unsupported_device_dialog(Device **device);
 const gchar* get_message_name(MessageID msgid);
-void create_pedal1_assign(void);
+void create_modifier_group (guint pos, guint id);
 
 #endif /* GDIGI_GUI_H */