Merge branch 'dev', remote-tracking branch 'upstream/dev' into dev
Fix the controlleradapter registerIPC bug.
Merge pull request #39 from hwchiu/core-bug

Core bug(controlleradapter missing registerIPC)
provide buffer time for detecting flow_delete
Fix empty actions field bug
Merge pull request #40 from starbops/dev

Fix empty actions field bug
Use Barrier Message to ensure switch finish processing FLOW_DELETE
to prevent from getting remove msg too late,lead to return wrong msg
Merge branch 'dev' into timesleep