JVET-L0646: Generalized bi-prediction (GBi)

cfg/encoder_lowdelay_vtm.cfg

cfg/encoder_randomaccess_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/CodingStatistics.h

source/Lib/CommonLib/CommonDef.h

source/Lib/CommonLib/ContextModelling.cpp

source/Lib/CommonLib/ContextModelling.h

source/Lib/CommonLib/Contexts.cpp

source/Lib/CommonLib/Contexts.h

source/Lib/CommonLib/InterPrediction.cpp

source/Lib/CommonLib/MotionInfo.h

source/Lib/CommonLib/Rom.cpp

source/Lib/CommonLib/Rom.h

source/Lib/CommonLib/Slice.h

source/Lib/CommonLib/TypeDef.h

source/Lib/CommonLib/Unit.cpp