Added ScanNetworks example, for all encryption types

Since this example doesn't need a connection to a network to see what
nets are out there, I went with one example rather than three.

WiFi/examples/ScanNetworks/ScanNetworks.ino

@@ -0,0 +1,79 @@
+/*
+ 
+ This example  prints the Wifi shield's MAC address, and
+ scans for available Wifi networks using the Wifi shield.
+ Every ten seconds, it scans again. It doesn't actually 
+ connect to any network, so no encryption scheme is specified.
+ 
+ Circuit:
+ * WiFi shield attached
+ 
+ created 13 July 2010
+ by dlf (Metodo2 srl)
+ modified 1 Mar 2012
+ by Tom Igoe
+ */
+
+
+#include <SPI.h>
+#include <WiFi.h>
+
+void setup() {
+  // initialize serial:
+  Serial.begin(9600);
+
+  // attempt to connect using WEP encryption:
+  Serial.println("Initializing Wifi...");
+  WiFi.begin("networName");
+  printMacAddress();
+
+
+  // scan for existing networks:
+  Serial.println("Scanning available networks...");
+  scanNetworks();
+}
+
+void loop() {
+  delay(10000);
+  // scan for existing networks:
+  Serial.println("Scanning available networks...");
+  scanNetworks();
+}
+
+void printMacAddress() {
+  // the MAC address of your Wifi shield
+  byte mac[6];                     
+  
+  // print your MAC address:
+  WiFi.macAddress(mac);
+  Serial.print("MAC: ");
+  Serial.print(mac[5],HEX);
+  Serial.print(":");
+  Serial.print(mac[4],HEX);
+  Serial.print(":");
+  Serial.print(mac[3],HEX);
+  Serial.print(":");
+  Serial.print(mac[2],HEX);
+  Serial.print(":");
+  Serial.print(mac[1],HEX);
+  Serial.print(":");
+  Serial.println(mac[0],HEX);
+}
+
+void scanNetworks() {
+  // scan for nearby networks:
+  Serial.println("** Scan Networks **");
+  byte numSsid = WiFi.scanNetworks();
+
+  // print the list of networks seen:
+  Serial.print("SSID List:");
+  Serial.println(numSsid);
+  // print the network number and name for each network found:
+  for (int thisNet = 0; thisNet<numSsid; thisNet++) {
+    Serial.print(thisNet);
+    Serial.print(") Network: ");
+    Serial.println(WiFi.SSID(thisNet));
+  }
+}
+
+