Final update from MJ

I have added everything except the changes in 08_scripts - as this now is beyond my skill level since the suggestions are about security issues and shlex and the benefits of ... if name ... boiler-plate. So it would be good for someone else to go through this and modify it as necessary. I'd just request that you don't complicate things more than necessary, as we want to be gentle to beginners and to encourage them. So I'd add extra stuff about nice features that you can get by going the extra mile rather than forcing that from the get go.