Add UTC EpochTime function

Author: heuman-a

NTPClient.cpp

@@ -136,6 +136,11 @@ unsigned long NTPClient::getEpochTime() const {
          ((millis() - this->_lastUpdate) / 1000); // Time since last update
 }
 
+unsigned long NTPClient::getUTCEpochTime() const {
+  return this->_currentEpoc + // Epoch returned by the NTP server
+         ((millis() - this->_lastUpdate) / 1000); // Time since last update
+}
+
 int NTPClient::getDay() const {
   return (((this->getEpochTime()  / 86400L) + 4 ) % 7); //0 is Sunday
 }

NTPClient.h

@@ -107,6 +107,10 @@ class NTPClient {
      */
     unsigned long getEpochTime() const;
 
+    /**
+     * @return time in seconds since Jan. 1, 1970
+     */
+    unsigned long getUTCEpochTime() const;
     /**
      * Stops the underlying UDP client
      */