add wifi manager esp32 (#414)

* add wifi manager esp32

lib/WiFiManager/examples/OnDemand/OnDemandConfigPortal/OnDemandConfigPortal.ino

@@ -0,0 +1,46 @@
+/**
+ * OnDemandConfigPortal.ino
+ * example of running the configPortal AP manually, independantly from the captiveportal
+ * trigger pin will start a configPortal AP for 120 seconds then turn it off.
+ * 
+ */
+#include <WiFiManager.h> // https://github.com/tzapu/WiFiManager
+
+// select which pin will trigger the configuration portal when set to LOW
+#define TRIGGER_PIN 0
+
+int timeout = 120; // seconds to run for
+
+void setup() {
+  // put your setup code here, to run once:
+  Serial.begin(115200);
+  Serial.println("\n Starting");
+  pinMode(TRIGGER_PIN, INPUT_PULLUP);
+}
+
+void loop() {
+  // is configuration portal requested?
+  if ( digitalRead(TRIGGER_PIN) == LOW) {
+    WiFiManager wm;    
+
+    //reset settings - for testing
+    //wifiManager.resetSettings();
+  
+    // set configportal timeout
+    wm.setConfigPortalTimeout(timeout);
+
+    if (!wm.startConfigPortal("OnDemandAP")) {
+      Serial.println("failed to connect and hit timeout");
+      delay(3000);
+      //reset and try again, or maybe put it to deep sleep
+      ESP.restart();
+      delay(5000);
+    }
+
+    //if you get here you have connected to the WiFi
+    Serial.println("connected...yeey :)");
+
+  }
+
+  // put your main code here, to run repeatedly:
+}

lib/WiFiManager/examples/OnDemand/OnDemandWebPortal/onDemandWebPortal.ino

@@ -0,0 +1,50 @@
+/**
+ * OnDemandWebPortal.ino
+ * example of running the webportal (always NON blocking)
+ */
+#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;
+
+bool portalRunning = false;
+
+void setup() {
+  // put your setup code here, to run once
+  Serial.begin(115200);
+  Serial.println("\n Starting");
+  pinMode(TRIGGER_PIN, INPUT_PULLUP);
+}
+
+void loop() {
+  checkButton();
+  // put your main code here, to run repeatedly:
+}
+
+void checkButton(){
+  // is auto timeout portal running
+  if(portalRunning){
+    wm.process();
+  }
+
+  // is configuration portal requested?
+  if(digitalRead(TRIGGER_PIN) == LOW) {
+    delay(50);
+    if(digitalRead(TRIGGER_PIN) == LOW) {
+      if(!portalRunning){
+        Serial.println("Button Pressed, Starting Portal");
+        wm.startWebPortal();
+        portalRunning = true;
+      }
+      else{
+        Serial.println("Button Pressed, Stopping Portal");
+        wm.startWebPortal();
+        portalRunning = false;
+      }
+    }
+  }
+}
+
+