Source: Use C++11 nullptr
refactor to use C++11 <cstddef>
nullptr.
KWSys is not changed as it appears intended to also work in non-C++11 projects.
As Brad notes:
- Tests/ need to compile as non-C++11 on old compilers.
- Source/LexerParser/ has generated files and we should not modify them.
Edited by scivision