message: RGBColor: allow string assignment in form of "0x...."
diff: @@ -75,7 +75,14 @@ RGBColor& RGBColor::operator=(string const& _hexCode)
  if (_hexCode.size() == 7 && _hexCode[0] == '#')
  {
  char* eptr = nullptr;
  - uint32_t value = strtoul(_hexCode.c_str() + 1, &eptr, 16);
  + uint32_t const value = strtoul(_hexCode.c_str() + 1, &eptr, 16);
  + if (eptr && *eptr == '\0')
  + *this = RGBColor{value};
  + }
  + if (_hexCode.size() >= 3 && _hexCode[0] == '0' && _hexCode[1] == 'x')
  + {
  + char* eptr = nullptr;
  + uint32_t const value = strtoul(_hexCode.c_str() + 2, &eptr, 16);
  if (eptr && *eptr == '\0')
  *this = RGBColor{value};
  }
  