Merge branch 'JVET-P0984-SubPic_Level_SEI' into 'master'

cfg/sei/subpicture_level.cfg

doc/software-manual.tex

source/App/EncoderApp/EncApp.cpp

source/App/EncoderApp/EncAppCfg.cpp

source/App/EncoderApp/EncAppCfg.h

source/Lib/CommonLib/SEI.cpp

source/Lib/CommonLib/SEI.h

source/Lib/CommonLib/TypeDef.h

source/Lib/DecoderLib/SEIread.cpp

source/Lib/DecoderLib/SEIread.h

source/Lib/EncoderLib/EncCfg.h

source/Lib/EncoderLib/EncGOP.cpp

source/Lib/EncoderLib/SEIEncoder.cpp

source/Lib/EncoderLib/SEIEncoder.h

source/Lib/EncoderLib/SEIwrite.cpp

source/Lib/EncoderLib/SEIwrite.h