Fix variable names

source/App/BitstreamExtractorApp/BitstreamExtractorApp.cpp

source/App/SEIFilmGrainApp/SEIFilmGrainApp.cpp

source/App/StreamMergeApp/StreamMergeApp.cpp

source/App/SubpicMergeApp/SubpicMergeApp.cpp

source/Lib/CommonLib/Contexts.cpp

source/Lib/CommonLib/Contexts.h

source/Lib/DecoderLib/BinDecoder.cpp

source/Lib/DecoderLib/BinDecoder.h

source/Lib/DecoderLib/CABACReader.cpp

source/Lib/DecoderLib/CABACReader.h

source/Lib/DecoderLib/NALread.h

source/Lib/EncoderLib/BinEncoder.cpp

source/Lib/EncoderLib/BinEncoder.h

source/Lib/EncoderLib/CABACWriter.cpp

source/Lib/EncoderLib/CABACWriter.h

source/Lib/EncoderLib/EncCu.cpp

source/Lib/EncoderLib/EncCu.h

source/Lib/EncoderLib/EncGOP.cpp

source/Lib/EncoderLib/NALwrite.cpp

source/Lib/EncoderLib/NALwrite.h