title: converting from std::string to uint8
body: <p>referring to the beautiful solutions provided here,
  <a href="https://stackoverflow.com/questions/1243428/convert-string-to-int-with-bool-fail-in-c">Convert string to int with bool/fail in C++</a>,  </p>
  
  <p>I would like to cast a std::string to a 8 bit number (unsigned or signed)
  The problem is that because 8 bit number is represented as a char so it is parsed wrong<br>
  (trying to parse anything above 1 digits - like 10 - fails)</p>
  
  <p>Any ideas?</p>