add wifi manager esp32 (#414)

* add wifi manager esp32

lib/WiFiManager/examples/NonBlocking/OnDemandNonBlocking/onDemandNonBlocking.ino

@@ -0,0 +1,63 @@
+/**
+ * OnDemandNonBlocking.ino
+ * example of running the webportal or configportal manually and non blocking
+ * trigger pin will start a webportal for 120 seconds then turn it off.
+ * startCP = true will start both the configportal AP and webportal
+ */
+#include <WiFiManager.h> // https://github.com/tzapu/WiFiManager
+
+// select which pin will trigger the configuration portal when set to LOW
+#define TRIGGER_PIN 0
+
+WiFiManager wm;
+
+unsigned int  timeout   = 120; // seconds to run for
+unsigned int  startTime = millis();
+bool portalRunning      = false;
+bool startAP            = false; // start AP and webserver if true, else start only webserver
+
+void setup() {
+  // put your setup code here, to run once
+  Serial.begin(115200);
+  Serial.println("\n Starting");
+  pinMode(TRIGGER_PIN, INPUT_PULLUP);
+}
+
+void loop() {
+  doWiFiManager();
+  // put your main code here, to run repeatedly:
+}
+
+void doWiFiManager(){
+  // is auto timeout portal running
+  if(portalRunning){
+    wm.process();
+    if((millis()-startTime) > (timeout*1000)){
+      Serial.println("portaltimeout");
+      portalRunning = false;
+      if(startAP){
+        wm.stopConfigPortal();
+      }  
+      else{
+        wm.stopWebPortal();
+      } 
+   }
+  }
+
+  // is configuration portal requested?
+  if(digitalRead(TRIGGER_PIN) == LOW && (!portalRunning)) {
+    if(startAP){
+      Serial.println("Button Pressed, Starting Config Portal");
+      wm.setConfigPortalBlocking(false);
+      wm.startConfigPortal();
+    }  
+    else{
+      Serial.println("Button Pressed, Starting Web Portal");
+      wm.startWebPortal();
+    }  
+    portalRunning = true;
+    startTime = millis();
+  }
+}
+
+