fix two mistakes in startServingClusterSubscriptionReqest and clusterDeliveryEndpoint.send
Implement and test function "window control by each client"
delete workLogging-huang.txt
 Add some modification in clusterDeliveryEndPoint.sendSubscriptionEvent
and send method.

Signed-off-by: huangruiqing <ruoyiqing1990@163.com>
Add three ways to implement the class: ClusterDeliveryEndPoint

Signed-off-by: huangruiqing <ruoyiqing1990@163.com>
remain one implement of "reentrantLock" for clusterDeliveryEndPoint.

Signed-off-by: huangruiqing <ruoyiqing1990@163.com>
Revise ClusterDeliveryEndPoint.java(with reentrantLock implementation)

Signed-off-by: huangruiqing <ruoyiqing1990@163.com>
modified ClusterDeliveryEndPoint.java (with concurrency map/queue)

Signed-off-by: huangruiqing <ruoyiqing1990@163.com>
Merge remote-tracking branch 'origin/huangruiqing' into liuyao_new

Conflicts:
	hedwig-server/src/main/java/org/apache/hedwig/server/delivery/ClusterDeliveryEndPoint.java
	hedwig-server/src/main/java/org/apache/hedwig/server/delivery/FIFODeliveryManager.java
little amend to finish merge