- Plugin sends Barrier msg every 100 async msgs (configurable thru config.ini: of...

- Plugin sends Barrier msg every 100 async msgs (configurable thru config.ini: of.barrierMessagePriorCount)
- SAL/plugin provide service to send Barrier message on demand. FM/application should invoke it explictly for sync purpose.
- LLDP interval is set to 5 mins (configurable thru config.ini: of.discoveryInterval)
- LLDP timeout is set to 1 min (configurable thru config.ini: of.discoveryTimeout). Retry 2 times.
- Switch liveness timeout is set to 60.5 sec (configurable thru config.ini: of.switchLivenessTimeout)
- SAL generates Request ID and passes it down to the plugin (IPluginInFlowProgrammerService: addFlowAsync(Node node, Flow flow, long rid), modifyFlowAsync(), deleteFlowAsync())
- STATS_REPLY timeout is configurable now thru config.ini of.messageResponseTimer
- Same priority messages are in FIFO manner
- Fix invalid ChassisID in LLDP packet
- Debugging messages
- Code style formatting
Signed-off-by: Jason Ye <yisye@cisco.com>