v0.2.1

• bundled BDUT 0.4.2 under include/bundled-software/bdut/ and wired C/C++ unit tests to it via assertion-macro shims (optional BDUT_ROOT / find_package(BDUT) override);
• prepare_cmake.sh — --bdut-root-dir for selecting an external BDUT tree;
• README.md — development dependency note for BDUT;