Show markdown description text on item detail 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)

src/coffee/controllers/item_group_controller.coffee

@@ -76,7 +76,6 @@ module.exports = class ItemGroupController extends BaseController
                     delay += @_delayStep
                 else
                     controller.model = item
-                    controller.refresh()
                 controllerIndex += 1
 
         while @_itemControllers.length > controllerIndex