DOC: add helpful comments

src/main/java/org/caosdb/datetime/UTCTimeZoneShift.java

@@ -127,15 +127,17 @@ public class UTCTimeZoneShift extends TimeZone {
   }
 
   /**
-   * Generate an ISO 8601 time zone offset string (e.g. +0200) from the given raw offset in
-   * milliseconds.
+   * Generate an ISO 8601 time zone offset string 
+   * (e.g. +0200) for the current time
    *
    * @param timezone - the time zone in question.
    * @return ISO 8601 time zone offset.
    */
   public static String getISO8601Offset(TimeZone timezone) {
     int divisor = 1000 * 60 * 60;
+    // get the offset of the given timezone to UTC at the current time
     int offset = timezone.getOffset(System.currentTimeMillis());
+    // convert the ms to the ISO format
     int sign = Integer.signum(offset);
     int h = Integer.divideUnsigned(sign * offset, divisor);
     int m = Integer.remainderUnsigned(sign * offset, divisor);