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.

gdigi.c

@@ -526,7 +526,9 @@ void push_message (GString *msg)
                              
             g_string_free(msg, TRUE);
 
-            create_pedal1_assign();
+            create_modifier_group(EXP_POSITION, EXP_ASSIGN1);
+            create_modifier_group(LFO1_POSITION, LFO_TYPE);
+            create_modifier_group(LFO2_POSITION, LFO_TYPE);
             return;
 
 
@@ -1505,7 +1507,7 @@ int main(int argc, char *argv[]) {
         g_mutex_free(message_queue_mutex);
     }
 
-    if (message_queue != NULL) {
+    if (message_queue != NULL && g_queue_get_length(message_queue)) {
         g_warning("%d unread messages in queue",
                   g_queue_get_length(message_queue));
         g_queue_foreach(message_queue, (GFunc) message_free_func, NULL);