Merge pull request #2615 from sorig/develop

Fixed typos in example descriptions
update the KL notebook
Merge pull request #2613 from yorkerlin/develop

update the KL notebook
Fixed compilation error under Mac OS X
Adjusted condition when TYPE_BOOL is restored
[skip ci]
Fixed macosx ifdef in ProtobufFile
Merge pull request #2621 from lisitsyn/fix/protobuf-macosx

Fixed macosx ifdef in ProtobufFile
better formatting in info message
Merge pull request #2625 from karlnapf/develop

better formatting in info message
Removed notebook that requires unavailable opencv version
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Merge pull request #2627 from Ialong/notebook_fix

Removed notebook that requires unavailable opencv version
Fix minor grammar errors in LMNN notebook.