Update NTPClient.cpp

Sorry I don't know if this is the correct format for submitting proposals. I seem to have this working now. I added a function LEAP_YEAR, getFormattedUTC and getFormattedDate. The getFormattedDate was from vismay2303 on arduino-libraries#119.  I have updates for NTPClient.h and keywords.txt

NTPClient.cpp

@@ -159,6 +159,79 @@ String NTPClient::getFormattedTime() const {
   return hoursStr + ":" + minuteStr + ":" + secondStr;
 }
 
+bool LEAP_YEAR(int y) {
+
+    if(y % 4 == 0)
+    {
+    	//Nested if else
+        if( y % 100 == 0)
+        {
+            if ( y % 400 == 0)
+                return true;
+		            //printf("%d is a Leap Year", y);
+            //else
+                //printf("%d is not a Leap Year", y);
+        }
+        else
+            return true;
+	        //printf("%d is a Leap Year", y );
+    }
+    else
+        //printf("%d is not a Leap Year", y);
+        return false;
+
+}
+
+String NTPClient::getFormattedDate() {
+  unsigned long rawTime = this->getEpochTime() / 86400L;  // in days
+  unsigned long days = 0, year = 1970;
+  uint8_t month;
+  static const uint8_t monthDays[]={31,28,31,30,31,30,31,31,30,31,30,31};
+
+  while((days += (LEAP_YEAR(year) ? 366 : 365)) <= rawTime)
+    year++;
+  rawTime -= days - (LEAP_YEAR(year) ? 366 : 365); // now it is days in this year, starting at 0
+  days=0;
+  for (month=0; month<12; month++) {
+    uint8_t monthLength;
+    if (month==1) { // february
+      monthLength = LEAP_YEAR(year) ? 29 : 28;
+    } else {
+      monthLength = monthDays[month];
+    }
+    if (rawTime < monthLength) break;
+    rawTime -= monthLength;
+  }
+  String monthStr = ++month < 10 ? "0" + String(month) : String(month); // jan is month 1  
+  String dayStr = ++rawTime < 10 ? "0" + String(rawTime) : String(rawTime); // day of month
+  return String(year) + "-" + monthStr + "-" + dayStr;
+}
+
+String NTPClient::getFormattedUTC() {
+  unsigned long rawTime = this->getEpochTime() / 86400L;  // in days
+  unsigned long days = 0, year = 1970;
+  uint8_t month;
+  static const uint8_t monthDays[]={31,28,31,30,31,30,31,31,30,31,30,31};
+
+  while((days += (LEAP_YEAR(year) ? 366 : 365)) <= rawTime)
+    year++;
+  rawTime -= days - (LEAP_YEAR(year) ? 366 : 365); // now it is days in this year, starting at 0
+  days=0;
+  for (month=0; month<12; month++) {
+    uint8_t monthLength;
+    if (month==1) { // february
+      monthLength = LEAP_YEAR(year) ? 29 : 28;
+    } else {
+      monthLength = monthDays[month];
+    }
+    if (rawTime < monthLength) break;
+    rawTime -= monthLength;
+  }
+  String monthStr = ++month < 10 ? "0" + String(month) : String(month); // jan is month 1  
+  String dayStr = ++rawTime < 10 ? "0" + String(rawTime) : String(rawTime); // day of month
+  return String(year) + "-" + monthStr + "-" + dayStr + "T" + getFormattedTime() + "Z";
+}
+
 void NTPClient::end() {
   this->_udp->stop();
 
@@ -207,4 +280,4 @@ void NTPClient::sendNTPPacket() {
 void NTPClient::setRandomPort(unsigned int minValue, unsigned int maxValue) {
   randomSeed(analogRead(0));
   this->_port = random(minValue, maxValue);
-}
+}