Method clearBuff

src/thundersvm/util/log.cpp:930–934

            }

            char* Str::clearBuff(char buff[], std::size_t lim) {
                STRCPY(buff, "", lim);
                ELPP_UNUSED(lim);  // For *nix we dont have anything using lim in above STRCPY macro
                return buff;
            }

/// @brief Converst wchar* to char*
///        NOTE: Need to free return value after use!