0024784: Move documentation in CDL files to proper location

Mostly duplicated comments were removed and missing ones were moved
into dedicated class CDL files.
Some more duplicated comments were removed from CDL files.
Correction of merge

src/Sweep/Sweep.cdl

@@ -35,14 +35,11 @@ is
     --     
 
     class NumShape;
-	---Purpose: A shape represented by an index.
-    
+
     class NumShapeTool;
-	---Purpose: Tool for NumShapes.
-    
+
     class NumShapeIterator;
-	---Purpose: Iterator for NumShapes.
-    
+
 end Sweep;