Add subscription and notification for resource changes; fix a bug while pserver node is uninstalled status
1. Trigger an event while resource changed, create a command handler to deal the event, let it can callback to SMO.
2. Create a mock SMO server with a simple html page to subscribe to O2IMS resource changing.
3. Fix a bug that when watch the pserver that it has an unavailable node.
Issue-ID: INF-238
Signed-off-by: Zhang Rong(Jon) <rong.zhang@windriver.com>
Change-Id: I13304656a721dbe5d4aec23200063e874eefa521