Prevent running the formatter without appropriate selection.

- VERBESSERT: Formatieren läßt sich nicht mehr starten, ohne daß Labor-Text markiert ist.

zaaReloaded2/Formatter/Formatter.cs

@@ -119,7 +119,7 @@ namespace zaaReloaded2.Formatter
         /// current position of the cursor).</param>
         public void Run()
         {
-            if (!CanRun) throw new InvalidOperationException("No laboratory data to format.");
+            if (!CanRun) throw new NoLaboratoryDataException("No laboratory data to format.");
 
             CreateParagraphStyle();
             _secondaryBuffer.ParagraphStyle = zaaReloaded2.Properties.Settings.Default.ParagraphStyleName;