Update the crafting page so that the check mark for each step only
appears when hovering over that step, and so that the check also has
some descriptive text helping the user understand what it does.
Any link inside a item detail page's markdown description which does
not have a URL will be assumed to be the name of an item covered by
Crafting Guide and an URL will be added to reference the appropiate
browse page.
* Update build process to *not* copy over prerendered pages during a
regular build (only during a `dist` build)
* Add dependency on npm "markdown" package and include it in the
scripts loaded in the default layout
* Update the Item model to be able to load from a *.cg file
* Add an ItemParser to process the `item.cg` file
* Update the general parser to be able to work with HereDoc-style
text blocks
* Add a markdown-specific stylesheet
* Add a sample of the `item.cg` file format (Advanced Crafting Table)
Andrew Miner