JVET-O1170: IBC virtual buffer

source/Lib/CommonLib/CodingStructure.h

source/Lib/CommonLib/InterPrediction.cpp

source/Lib/CommonLib/InterPrediction.h

source/Lib/CommonLib/TypeDef.h

source/Lib/CommonLib/UnitTools.cpp

source/Lib/CommonLib/UnitTools.h

source/Lib/DecoderLib/DecCu.cpp

source/Lib/DecoderLib/DecLib.cpp

source/Lib/DecoderLib/DecSlice.cpp

source/Lib/EncoderLib/EncCu.cpp

source/Lib/EncoderLib/InterSearch.cpp

source/Lib/EncoderLib/InterSearch.h