One other thing -- I've just been trying out the Markdown export and preview and couldn't get it to work at first. I think I've just tracked down why...
It seems you have Tinderbox 7.app on your desktop, so you've coded $HTMLPreviewCommand to point to within the app bundle there.
I have it installed in /Applications, so I keep getting 'command not found errors'. When I updated it to my path, it works fine.
I.e. for the markdown prototype I have:
This may be more generally applicable as a default for the starter as I think most people install into Applications?
Another minor point — took me a while to work out where the Preview pane was for quick viewing of the markdown rendering (Mark B mentions it in the Release Notes). Of course I'd forgotten that you need to use Window > Show Text Pane Selector.
Of course, you can't turn the starter file into a tutorial, but I wondered if other people will be as flummoxed as I was at first, so a very quick note in the Markdown prototype text ('To see the preview make sure you've selected 'Show Text Pane Selector' in the Window menu') might help?
Thanks again for doing the starter file -- leafing through it has reminded me of many features I never use, and that's a great help in itself.