add EPLHelpers.makeTime()

src/main/java/EPLHelpers.java

@@ -35,6 +35,13 @@ public class EPLHelpers {
         return timeFormatter.parseDateTime(time);
     }
 
+    /**
+     * Create a DateTime object from time in millis.
+     */
+    public static DateTime makeTime(Long time) {
+        return new DateTime(time);
+    }
+
     /**
      * Return true if the time portion of 'now' is between the time
      * portion of 'start' and 'end'.