To remove boost dependency, `-DMSGPACK_USE_BOOST=OFF` for cmake.
By default, `-DMSGPACK_USE_BOOST` is `ON`.
NOTE: In order to build tests `-DMSGPACK_USE_BOOST=ON` is required.
For C++ compiler, the option `-DMSGPACK_NO_BOOST` is required to remove
boost.
- Enhance CMakeLists.txt files.
- Move to Boost Test from Google Test to support pre-C++11 compilers.
- Add more configurations on CI matrix builds.
- Other minor fixes