make equalizer a string + make sure output-i2s is exited

- Can't really use BLOB (creates issue with HTTP visualizer)
- Player was stuck after WiFi loss b/c with some race conditions, BT deinit crashes and creates the reboot wanted after 5*5 failures. But when BT does not crash, reboot was not happening and player was stuck with slimproto not exited and player not rebooted

components/squeezelite/output_i2s.c

@@ -573,10 +573,11 @@ static void output_thread_i2s(void *arg) {
 		SET_MIN_MAX( TIME_MEASUREMENT_GET(timer_start),i2s_time);
 		
 	}
-	
-	vTaskDelete(NULL);
+
 	if (spdif.enabled) free(spdif.buf);
 	ended = true;
+
+	vTaskDelete(NULL);	
 }
 
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