Re-ordered the parameters in the stream: [energy, pitch index, pitch gains]

Also fixed a bug that was exposed by the change (and removed some warnings)

libcelt/modes.c

@@ -160,6 +160,9 @@ int celt_mode_info(const CELTMode *mode, int request, celt_int32_t *value)
       case CELT_GET_NB_CHANNELS:
          *value = mode->nbChannels;
          break;
+      default:
+         return CELT_BAD_ARG;
    }
+   return CELT_OK;
 }