Version 2 available to download

You can now download a copy of JDMC version 2. Expect this version to change often as it's not yet finished - but it seems important to get it out there as soon as possible as it contains three new sections to cover topics that some readers have asked me about. There are also corrections, additions and rewritten parts in the existing sections, and I've added many more active links for those reading on screen (both online and the downloaded PDF).