incremental update of changelog in preparation for train-2012.05.25

ChangeLog

 train-2012.05.25 (in progress):
-  *
+  * many KPI improvements: #1597, #1613
+  * code cleanup: #1599, #1602
+  * verification links sent before deployment, should still work after - transitional code required by issue #1000: #1592
+  * repair load_gen: #1596
+  * fixes to mysql reconnection logic - processes can now reconnect while out of pool and only having /__heartbeat__ polled: #1608
 
 train-2012.05.14:
   * Password is now requested in dialog for new user signup: #1000, #290