SHAPE_LINE_CHAIN: Remove element access

This is the first step to allowing non-segments in the line chain.
External routines cannot be allowed to change the line chain without
going through the internal routines.  To accomplish this, we remove the
Vertex() and Point() access routines and only leave the const versions.
Transformations are given for both points as well as the chain itself.

common/gr_basic.cpp

@@ -71,8 +71,7 @@ static const bool NOT_FILLED = false;
 GR_DRAWMODE g_XorMode = GR_NXOR;
 
 
-static void ClipAndDrawPoly( EDA_RECT * ClipBox, wxDC * DC, wxPoint Points[],
-                             int n );
+static void ClipAndDrawPoly( EDA_RECT* ClipBox, wxDC* DC, const wxPoint* Points, int n );
 
 /* These functions are used by corresponding functions
  * ( GRSCircle is called by GRCircle for instance) after mapping coordinates
@@ -428,7 +427,7 @@ void GRFilledSegment( EDA_RECT* aClipBox, wxDC* aDC, wxPoint aStart, wxPoint aEn
 }
 
 
-static bool IsGRSPolyDrawable( EDA_RECT* ClipBox, int n, wxPoint Points[] )
+static bool IsGRSPolyDrawable( EDA_RECT* ClipBox, int n, const wxPoint* Points, )
 {
     if( !ClipBox )
         return true;
@@ -470,9 +469,8 @@ static bool IsGRSPolyDrawable( EDA_RECT* ClipBox, int n, wxPoint Points[] )
 /*
  * Draw a new polyline and fill it if Fill, in screen space.
  */
-static void GRSPoly( EDA_RECT* ClipBox, wxDC* DC, int n, wxPoint Points[],
-                     bool      Fill, int width,
-                     COLOR4D Color, COLOR4D BgColor )
+static void GRSPoly( EDA_RECT* ClipBox, wxDC* DC, int n, const wxPoint* Points, bool Fill,
+        int width, COLOR4D Color, COLOR4D BgColor )
 {
     if( !IsGRSPolyDrawable( ClipBox, n, Points ) )
         return;
@@ -503,11 +501,8 @@ static void GRSPoly( EDA_RECT* ClipBox, wxDC* DC, int n, wxPoint Points[],
 /*
  * Draw a new closed polyline and fill it if Fill, in screen space.
  */
-static void GRSClosedPoly( EDA_RECT* aClipBox, wxDC* aDC,
-                           int       aPointCount, wxPoint aPoints[],
-                           bool      aFill, int aWidth,
-                           COLOR4D   aColor,
-                           COLOR4D   aBgColor )
+static void GRSClosedPoly( EDA_RECT* aClipBox, wxDC* aDC, int aPointCount, const wxPoint* aPoints,
+        bool aFill, int aWidth, COLOR4D aColor, COLOR4D aBgColor )
 {
     if( !IsGRSPolyDrawable( aClipBox, aPointCount, aPoints ) )
         return;
@@ -543,8 +538,8 @@ static void GRSClosedPoly( EDA_RECT* aClipBox, wxDC* aDC,
 /*
  * Draw a new polyline and fill it if Fill, in drawing space.
  */
-void GRPoly( EDA_RECT* ClipBox, wxDC* DC, int n, wxPoint Points[],
-             bool Fill, int width, COLOR4D Color, COLOR4D BgColor )
+void GRPoly( EDA_RECT* ClipBox, wxDC* DC, int n, const wxPoint* Points, bool Fill, int width,
+        COLOR4D Color, COLOR4D BgColor )
 {
     GRSPoly( ClipBox, DC, n, Points, Fill, width, Color, BgColor );
 }
@@ -553,15 +548,15 @@ void GRPoly( EDA_RECT* ClipBox, wxDC* DC, int n, wxPoint Points[],
 /*
  * Draw a closed polyline and fill it if Fill, in object space.
  */
-void GRClosedPoly( EDA_RECT* ClipBox, wxDC* DC, int n, wxPoint Points[],
-                   bool Fill, COLOR4D Color, COLOR4D BgColor )
+void GRClosedPoly( EDA_RECT* ClipBox, wxDC* DC, int n, const wxPoint* Points, bool Fill,
+        COLOR4D Color, COLOR4D BgColor )
 {
     GRClosedPoly( ClipBox, DC, n, Points, Fill, 0, Color, BgColor );
 }
 
 
-void GRClosedPoly( EDA_RECT* ClipBox, wxDC* DC, int n, wxPoint Points[],
-                   bool Fill, int width, COLOR4D Color, COLOR4D BgColor )
+void GRClosedPoly( EDA_RECT* ClipBox, wxDC* DC, int n, const wxPoint* Points, bool Fill, int width,
+        COLOR4D Color, COLOR4D BgColor )
 {
     GRSClosedPoly( ClipBox, DC, n, Points, Fill, width, Color, BgColor );
 }
@@ -958,7 +953,7 @@ void GRSFilledRect( EDA_RECT* aClipBox, wxDC* aDC, int x1, int y1, int x2, int y
  */
 #include <SutherlandHodgmanClipPoly.h>
 
-void ClipAndDrawPoly( EDA_RECT* aClipBox, wxDC* aDC, wxPoint aPoints[], int n )
+void ClipAndDrawPoly( EDA_RECT* aClipBox, wxDC* aDC, const wxPoint* Points, int n )
 {
     if( aClipBox == NULL )
     {