NewFeatures: Chronological entries

DWiki now remembers the name and URL for links that you write with [[...|...]] and thereafter allows you to omit one side of the |, at which point it will fill in the remembered values. This means that if you want to link to Google a lot in your document, you only have to write (eg) the URL once, and can thereafter refer to Google much more compactly.

This does collide a little bit with using [[...|]] to write totally unstyled text: it only comes out unstyled if it's not already been used as the name of a link.

For now I will live with that.