Implement ItemComment view model and view.

- NEU: Optionale Kommentare zu Laborwerten.

Tests/Controller/Comments/CommentPoolTest.cs

@@ -48,13 +48,13 @@ namespace Tests.Controller.Comments
         public void BuildingCommentRaisesEvent()
         {
             ItemComment i = CommentPool.Default.GetCommentFor("item \"<>\"");
-            bool eventRaised = false;
+            int eventRaised = 0;
             CommentPool.Default.FillInComment += (sender, args) =>
             {
-                eventRaised = true;
+                eventRaised += 1;
             };
             string comment = i.BuildComment();
-            Assert.IsTrue(eventRaised);
+            Assert.AreEqual(1, eventRaised);
         }
     }
 }