0025418: Debug output to be limited to OCC development environment

Macros ending on "DEB" are replaced by OCCT_DEBUG across OCCT code; new macros described in documentation.
Macros starting with DEB are changed to start with "OCCT_DEBUG_".
Some code cleaned.

src/GccAna/GccAna_Circ2d2TanRad_1.cxx

@@ -394,7 +394,7 @@ GccAna_Circ2d2TanRad::
 		gp_Ax2d axe(Center,dirx);
 		cirsol(NbrSol) = gp_Circ2d(axe,Radius);
 //              ======================================
-#ifdef DEB
+#ifdef OCCT_DEBUG
 		gp_Dir2d dc1(center1.XY()-Center.XY());
 #endif
 		gp_Dir2d dc2(origin2.XY()-Center.XY());

src/GccAna/GccAna_Circ2d2TanRad_2.cxx

@@ -192,7 +192,7 @@ GccAna_Circ2d2TanRad::
 	      else { qualifier1(NbrSol) = GccEnt_enclosing; }
 	      qualifier2(NbrSol) = GccEnt_noqualifier;
 	      dir1 = gp_Dir2d(Center.XY()-center1.XY());
-#ifdef DEB
+#ifdef OCCT_DEBUG
 	      gp_Dir2d dir2(Center.XY()-Point2.XY());
 #endif
 	      if ((Center.Distance(center1) > C1.Radius()) &&

src/GccAna/GccAna_Circ2d3Tan_1.cxx

@@ -86,7 +86,7 @@ GccAna_Circ2d3Tan::
   Standard_Real R1 = C1.Radius();
   Standard_Real R2 = C2.Radius();
   gp_Pnt2d center1(C1.Location());
-#ifdef DEB
+#ifdef OCCT_DEBUG
   gp_Pnt2d center2(C2.Location());
 #else
   C2.Location() ;

src/GccAna/GccAna_Circ2d3Tan_6.cxx

@@ -89,7 +89,7 @@ GccAna_Circ2d3Tan::
      Standard_Integer nbsolution1 = Bis1.NbSolutions();
      Handle(GccInt_Bisec) Sol2 = Bis2.ThisSolution();
      for (Standard_Integer i = 1 ; i <=  nbsolution1; i++) {
-#ifdef DEB
+#ifdef OCCT_DEBUG
        gp_Lin2d Sol1(Bis1.ThisSolution(i));
 #else
        Bis1.ThisSolution(i) ;

src/GccAna/GccAna_Circ2d3Tan_8.cxx

@@ -86,7 +86,7 @@ GccAna_Circ2d3Tan::
      gp_Lin2d linint1(Bis1.ThisSolution());
      Handle(GccInt_Bisec) Sol2 = Bis2.ThisSolution();
      GccInt_IType typ2 = Sol2->ArcType();
-#ifdef DEB
+#ifdef OCCT_DEBUG
      gp_Lin2d linintb(Bis1.ThisSolution());
 #else
      Bis1.ThisSolution() ;