Added two comments to explain the while-loop in now()

Time.cpp

@@ -248,7 +248,9 @@ time_t sysUnsyncedTime = 0; // the time sysTime unadjusted by sync
 
 
 time_t now() {
-  while (millis() - prevMillis >= 1000){      
+	// calculate number of seconds passed since last call to now()
+  while (millis() - prevMillis >= 1000) {
+		// millis() and prevMillis are both unsigned ints thus the subtraction will always be the absolute value of the difference
     sysTime++;
     prevMillis += 1000;	
 #ifdef TIME_DRIFT_INFO