adds WiFi.getPersistent() (#3857)

Author: tablatronix

libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp

@@ -303,6 +303,13 @@ void ESP8266WiFiGenericClass::persistent(bool persistent) {
     _persistent = persistent;
 }
 
+/**
+ * gets the persistent state
+ * @return bool
+ */
+bool ESP8266WiFiGenericClass::getPersistent(){
+    return _persistent;
+}
 
 /**
  * set new mode

libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.h

@@ -99,7 +99,7 @@ class ESP8266WiFiGenericClass {
 
         int hostByName(const char* aHostname, IPAddress& aResult);
         int hostByName(const char* aHostname, IPAddress& aResult, uint32_t timeout_ms);
-
+        bool getPersistent();
     protected:
 
         friend class ESP8266WiFiSTAClass;