merge JVET-M0427 into master

cfg/encoder_intra_vtm.cfg

source/App/EncoderApp/EncApp.cpp

source/App/EncoderApp/EncAppCfg.cpp

source/App/EncoderApp/EncAppCfg.h

source/Lib/CommonLib/Buffer.cpp

source/Lib/CommonLib/Buffer.h

source/Lib/CommonLib/CodingStructure.cpp

source/Lib/CommonLib/CodingStructure.h

source/Lib/CommonLib/CommonDef.h

source/Lib/CommonLib/Picture.cpp

source/Lib/CommonLib/Picture.h

source/Lib/CommonLib/RdCost.cpp

source/Lib/CommonLib/RdCost.h

source/Lib/CommonLib/Reshape.cpp

source/Lib/CommonLib/Reshape.h

source/Lib/CommonLib/Slice.cpp

source/Lib/CommonLib/Slice.h

source/Lib/CommonLib/TypeDef.h

source/Lib/CommonLib/Unit.cpp

source/Lib/CommonLib/Unit.h