0024830: Remove redundant keyword 'mutable' in CDL declarations

Redundant keyword 'mutable' removed in CDL files.
In IGESConvGeom_GeomBuilder, unused methods MakeXY() and MakeXYZ() removed.
Method StepAP214_AutoDesignGroupAssignment::Init() replicating same method of the base class is removed as it causes CDL extraction error after above (seemingly irrelevant) changes.

src/IntWalk/IntWalk_IWLine.cdl

@@ -51,7 +51,7 @@ is
 
     Create (theAllocator: Allocator from IntSurf = 0)
     
-    	returns mutable IWLine;
+    	returns IWLine;
 
 
     Reverse(me : mutable)
@@ -154,7 +154,7 @@ is
     
 	---Purpose: Returns the LineOn2S contained in the walking line.
     
-    	returns mutable LineOn2S from IntSurf
+    	returns LineOn2S from IntSurf
 	---C++: return const&
     	---C++: inline
 	

src/IntWalk/IntWalk_IWalking.cdl

@@ -215,7 +215,7 @@ is
 		    
     TestArretCadre(me : in out; Umult  : SequenceOfReal from TColStd;
                                 Vmult  : SequenceOfReal from TColStd;
-                                Line   : mutable TheIWLine;
+                                Line   : TheIWLine;
 				Section: in out TheIWFunction;
                                 UV     : in out Vector from math;
                                 Irang  : out Integer from Standard)
@@ -244,7 +244,7 @@ is
                           Psol   : PntOn2S from IntSurf;
 			  Pnts1  : ThePOPIterator;
  			  Section: in out TheIWFunction;
-                          Line   : mutable TheIWLine)
+                          Line   : TheIWLine)
     is static protected;	
 
     ComputeCloseLine(me : in out; Umult  : SequenceOfReal from TColStd;
@@ -257,7 +257,7 @@ is
 
     AddPointInCurrentLine(me ; N           : Integer from Standard;
                                PathPnt     : ThePointOfPath;
-                               CurrentLine : mutable TheIWLine)
+                               CurrentLine : TheIWLine)
     is static protected;
 
     MakeWalkingPoint(me : in out ; Case    : Integer from Standard;

src/IntWalk/IntWalk_PWalking.cdl

@@ -165,7 +165,7 @@ is
 
     Line(me)
     
-    	returns mutable LineOn2S from IntSurf
+    	returns LineOn2S from IntSurf
 	---C++: inline
 	---C++: return const&