Add a "Random Item" link to the breadcrumb bar

fixes #216

src/client/site/item_page/item_page_controller.coffee

@@ -68,6 +68,15 @@ module.exports = class ItemPageController extends PageController
             $("<b>#{display.itemName}</b>")
         ]
 
+    getExtraNav: ->
+        console.warn "getExtraNav()"
+        itemSlug = @_modPack.chooseRandomItem()
+        console.warn "    itemSlug: #{itemSlug}"
+        return null unless itemSlug?
+
+        itemDisplay = @_modPack.findItemDisplay itemSlug
+        return $("<a href='#{itemDisplay.itemUrl}'>Random Item</a>")
+
     getMetaDescription: ->
         return null unless @_itemSlug?
         display = @_modPack.findItemDisplay @_itemSlug
@@ -83,6 +92,10 @@ module.exports = class ItemPageController extends PageController
 
     # BaseController Overrides #####################################################################
 
+    onDidModelChange: ->
+        @trigger c.event.change
+        super
+
     onDidRender: ->
         options                      = imageLoader:@_imageLoader, modPack:@_modPack, router:@_router, show:false
         @_multiblockController       = @addChild MultiblockViewerController, '.view__multiblock_viewer', options