Added Serial port check to all examples using Serial statements in the setup

libraries/Ethernet/examples/TelnetClient/TelnetClient.ino

@@ -13,6 +13,7 @@
  * Ethernet shield attached to pins 10, 11, 12, 13
  
  created 14 Sep 2010
+ modified 2 Apr 2012
  by Tom Igoe
  
  */
@@ -38,8 +39,10 @@ EthernetClient client;
 void setup() {
   // start the Ethernet connection:
   Ethernet.begin(mac, ip);
-  // start the serial library:
+ // Open serial communications and wait for port to open:
   Serial.begin(9600);
+  while(!Serial) ;
+
   // give the Ethernet shield a second to initialize:
   delay(1000);
   Serial.println("connecting...");