Improving variable name.

examples/RestClient/ThingSpeak/ThingSpeak.ino

@@ -7,14 +7,14 @@ This example show the interaction between the Ciao Library and the Thingspeak Cl
 To run the example you need to register an account on thingspeak.com and create a 
 new channel by clicking "Channels" section in the website (Channels -> My Channels -> New Channel). 
 In the new channel you need to add two fields. The first one refers to the humidity data and the second one to the temperature value.
-After that, replace the "XXXXXXXXX" value of APIKEY_THINGSPEAK with "Write API key" value reported in the API Keys section of the channel. 
+After that, replace the "XXXXXXXXX" value of WRITE_APIKEY_THINGSPEAK with "Write API key" value reported in the API Keys section of the channel. 
 
 */
 
 #define CONNECTOR     "rest" 
 #define SERVER_ADDR   "api.thingspeak.com"
 
-#define APIKEY_THINGSPEAK  "XXXXXXXXXXXXX"
+#define WRITE_APIKEY_THINGSPEAK  "XXXXXXXXXXXXX"
 
 short hum = 60;
 short temp = 22;
@@ -27,7 +27,7 @@ void setup() {
 void loop() {
 
     String uri = "/update?api_key=";
-    uri += APIKEY_THINGSPEAK;
+    uri += WRITE_APIKEY_THINGSPEAK;
     uri += "&field1=";
     uri += String(hum);
     uri += "&field2=";