Update index.md

HfT Building Models/Sketchup/Casper/index.md

 Note:
 
-All files herein are created for
-
-    Sketchup 8 and above
+All files herein require     **Sketchup 8 or above**
     
 
 *  CityGML surface types are classified in different layers and are visible and usable in native Sketchup.
-*  Further CityGML specific features ( like Location Info, Surface Types, Grouping and Attributes ) are stored in the models but are only visible, editable and usable with
-
-    CityEditor plugin from 3DIS ( see https://www.3dis.de/cityeditor/ )
+*  Further CityGML specific features ( like Location Info, Surface Types, Grouping and Attributes ) are stored in the models but are only visible, editable and usable with **CityEditor plugin from 3DIS ( see [https://www.3dis.de/cityeditor]  )**
 
 **Note the licensing conditions in the LICENSE file ( also referenced to in the model info of each Sketchup file )**
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