noLink -> addLink

Replace the variable "noLink" by "addLink". This saves you the
two seconds for thinking about the multiple negation
`#unless noLink #else ..`. `#if addLink #else ..` is more
readily grasped.
Just for thought. We haven't yet decided if one-line comments or one-sentence comments should have dot at the end or not. :-) In code style it is written that it should be without dot, but it makes things hard to decide sometimes. So, this is one thing also which could be done: unify the style of all comments and update the code style on the wiki accordingly.