Fix #735: remove constrained_intra_pred_flag

source/App/EncoderApp/EncApp.cpp

source/App/EncoderApp/EncAppCfg.cpp

source/App/EncoderApp/EncAppCfg.h

source/Lib/CommonLib/IntraPrediction.cpp

source/Lib/CommonLib/Slice.cpp

source/Lib/CommonLib/Slice.h

source/Lib/DecoderLib/VLCReader.cpp

source/Lib/EncoderLib/EncCfg.h

source/Lib/EncoderLib/EncLib.cpp

source/Lib/EncoderLib/VLCWriter.cpp