Add some links and new cards+What's special about Wagn?

In Wagn, links aren't just part of content, they're also part of structure.  Links are tightly tracked and can be queried.

So it's important to keep link quality high.  If someone changes the name of a card, we need to make sure the links are still correct.  So we offer the user the chance to change all the links at the time of the update, and that change itself is tracked.

Our mixture of link and inclusion markup with WYSIWYG (What You See Is What You Get) rich text editing is also pretty unusual.  The idea is to hide as little as possible, and to give special emphasis to links and inclusions, on which we are able to build our structure.