Function trim

src/stringutils.cpp:21–30

  }

  std::string trim(const std::string& s, char c)
  {
    auto b = s.begin();
    auto e = s.end();
    e--;
    while(*b == c) b++;
    while(*e == c) e--;
    if(e++ >= b) return std::string(b, e);
    return "";
  }

  std::string lower(const std::string& s)
  {