message: Fixed compiler error
  This code should never have used NULL, but checked for 0 as it is not
  dealing with pointers.
diff: @@ -215,7 +215,7 @@ float PQRRequest::getMolMass(QString formula) {
  }
  }
  //if the next letter is another uppercase or null, the current subscript is 1
  - else if (isupper(str[i + 1]) || str[i + 1] == nullptr) {
  + else if (isupper(str[i + 1]) || str[i + 1] == 0) {
  subscript = 1;
  element = { str[i] };
  }
  