Added WiFi callback functionality

HomeSpan will call a user-defined function upon establishing WiFi connectivity.
Set function with homeSpan.setWifiCallback(f), where f must be of form void f().

src/HomeSpan.cpp

@@ -496,6 +496,9 @@ void Span::checkConnect(){
     statusLED.on();
   }
 
+  if(wifiCallback)
+    wifiCallback();
+  
 } // initWiFi
 
 ///////////////////////////////

src/HomeSpan.h

@@ -103,6 +103,7 @@ struct Span{
   char qrID[5]="";                                            // Setup ID used for pairing with QR Code
   boolean otaEnabled=false;                                   // enables Over-the-Air ("OTA") updates
   char otaPwd[33];                                            // MD5 Hash of OTA password, represented as a string of hexidecimal characters
+  void (*wifiCallback)()=NULL;                                // optional callback function to invoke once WiFi connectivity is established
 
   WiFiServer *hapServer;                            // pointer to the HAP Server connection
   Blinker statusLED;                                // indicates HomeSpan status
@@ -156,6 +157,7 @@ struct Span{
   void enableOTA(){otaEnabled=true;}                                      // enables Over-the-Air updates
   void setSketchVersion(const char *sVer){sketchVersion=sVer;}            // set optional sketch version number
   const char *getSketchVersion(){return sketchVersion;}                   // get sketch version number
+  void setWifiCallback(void (*f)()){wifiCallback=f;}                      // sets an optional user-defined function to call once WiFi connectivity is established
 };
 
 ///////////////////////////////

src/src.ino

@@ -14,8 +14,9 @@ void setup() {
   homeSpan.setPortNum(1200);
   homeSpan.setMaxConnections(16);
 //  homeSpan.setQRID("One1");
-//  homeSpan.enableOTA();
-  homeSpan.setSketchVersion("Test 1.2.3");
+  homeSpan.enableOTA();
+  homeSpan.setSketchVersion("Test 1.2.4");
+  homeSpan.setWifiCallback(wifiEstablished);
 
   homeSpan.begin(Category::Lighting,"HomeSpanTest");
 
@@ -44,3 +45,9 @@ void loop(){
   homeSpan.poll();
   
 } // end of loop()
+
+//////////////////////////////////////
+
+void wifiEstablished(){
+  Serial.println("\n\nIN CALLBACK FUNCTION\n\n");
+}