Change MDNS_NAME to SYSTEM_NAME

This value will be used as the MQTT client name when MQTT gets implemented.

config.h.sample

@@ -24,6 +24,8 @@
  *
  */
 
+#include "consts.h"
+
 // The SSID (name) and password of the WiFi network you want to connect to
 #define WIFI_SSID "YourWiFiName"
 #define WIFI_PASS "YourWiFiPass"
@@ -31,7 +33,7 @@
 // The mDNS hostname you want this station to be visible as.  This should be
 // different for each station you install (e.g. if you want to measure the
 // temperature and humidity of each room separately)
-#define MDNS_NAME "internal-hostname"
+#define SYSTEM_NAME "internal-hostname"
 
 // If you have a DHT temperature+humidity sensor of this type will be used,
 // remove the #undef line and uncomment one of DHT11 or DHT22.  You also have