Add C++ libraries in core - string `Stream.cpp`and `Stream.h` and - stream `Stream.cpp`and `Stream.h`. Corresponding files for Wiring are [Stream.cpp](https://github.com/WiringProject/Wiring/blob/master/framework/cores/Common/Stream.cpp) and [Stream.h](https://github.com/WiringProject/Wiring/blob/master/framework/cores/Common/Stream.h), [WString.cpp](https://github.com/WiringProject/Wiring/blob/master/framework/cores/Common/WString.cpp) and [WString.h](https://github.com/WiringProject/Wiring/blob/master/framework/cores/Common/WString.h).
Add C++ libraries in core
Stream.cppandStream.handStream.cppandStream.h.Corresponding files for Wiring are Stream.cpp and Stream.h, WString.cpp and WString.h.