improve javadoc

src/com/angryelectron/thingspeak/Entry.java

@@ -231,12 +231,13 @@ public void setTweet(String tweet) {
     }
 
     /**
-     * Set the created_at date of an entry, since the rate limit of the public Thingspeak server is 15 sec
-     * @param created_at date which will be send to thingspeak
+     * Set the created date of an entry. If not explicitly set, the channel update time is used.
+	 * Useful when entries are not created and updated at the same time (offline mode, queuing to avoid rate-limiting, etc.)
+     * @param created date which will be send to thingspeak
      */
-    public void setCreated_at(Date created_at) {
-        this.created_at = created_at;
-        updateMap.put("created_at", created_at);
+    public void setCreated(Date created) {
+        this.created_at = created;
+        updateMap.put("created_at", created);
     }
 
     /**