Add static IP config, prepare for web config support

src/e131.h

@@ -24,16 +24,21 @@
 #define E131_H_
 
 #include "Arduino.h"
+#include "config.h"
 
 /* Network interface detection.  WiFi for ESP8266 and Ethernet for AVR */
-//#   include <WiFi.h>
+#ifdef INT_WIFI
+    #include <WiFi.h>
+#endif
 //#   include <WiFiMulti.h>
 //#   include <WiFiUdp.h>
-#   include <W5500lwIP.h>
+#ifdef INT_ETHERNET
+    #include <W5500lwIP.h>
+#endif
 #   include <lwip/ip_addr.h>
 #   include <lwip/igmp.h>
 #   define _UDP WiFiUDP
-#   define INT_ETHERNET
+//#   define INT_ETHERNET
 
 
 #define NO_DOUBLE_BUFFER 1