Port reduction crash fix
Add a event LibraryLoadFailed to LibraryServices
Remove LibraryLoadStatus
Merge pull request #679 from ambarish-prakash/CodeBlockNodePort

Port reduction crash fix
Merge pull request #681 from ke-yu/ChocoButter

Support to load ds file
Merge remote-tracking branch 'upstream/ChocoButter' into ChocoButter
Add EngineController to coodinate the interactions among DS components
Update DS test cases