Add retry button for when fetching fails

src/app/available-packages-config-panel.coffee

@@ -9,15 +9,28 @@ class AvailablePackagesConfigPanel extends ConfigPanel
     @div class: 'available-packages', =>
       @div outlet: 'loadingArea', class: 'alert alert-info loading-area', =>
         @span 'Loading available packages\u2026'
+      @div outlet: 'errorArea', class: 'alert alert-error', =>
+        @span 'Error fetching available packages.'
+        @button outlet: 'retry', class: 'btn btn-mini btn-retry', 'Retry'
+      @div outlet: 'packagesArea'
 
   initialize: (@packageEventEmitter) ->
+    @retry.on 'click', => @refresh()
+    @refresh()
+
+  refresh: ->
+    @loadingArea.show()
+    @errorArea.hide()
+
     packageManager.getAvailable (error, @packages=[]) =>
       @loadingArea.hide()
       if error?
+        @errorArea.show()
         console.error(error.stack ? error)
       else
+        @packagesArea.empty()
         for pack in @packages
-          @append(new PackageConfigView(pack, @packageEventEmitter))
-      @packageEventEmitter.trigger('available-packages-loaded', [@packages])
+          @packagesArea.append(new PackageConfigView(pack, @packageEventEmitter))
+      @packageEventEmitter.trigger('available-packages-loaded', @packages)
 
   getPackageCount: -> @packages.length

static/config.less

@@ -143,6 +143,10 @@
     }
   }
 
+  .btn-retry {
+    margin-left: 10px;
+  }
+
   .readme {
     margin-top: 10px;
   }