Pcbnew: fix a minor bug: in zones with no net, only the zone clerance was used...

Pcbnew: fix a minor bug: in zones with no net, only the zone clerance was used to created clearence,  regardless the pad or footprint local clerance.
Very minor other fixes.

common/class_marker_base.cpp

@@ -20,7 +20,7 @@
 
 // Default marquer shape:
 const int      M_SHAPE_SCALE = 6;     // default scaling factor for MarkerShapeCorners coordinates
-const int CORNERS_COUNT = 8;
+const unsigned CORNERS_COUNT = 8;
 /* corners of the default shape
  * actual coordinates are these values * .m_ScalingFactor
 */

pcbnew/board_items_to_polygon_shape_transform.cpp

@@ -54,7 +54,7 @@ static void addTextSegmToPoly( int x0, int y0, int xf, int yf )
 void BOARD::ConvertBrdLayerToPolygonalContours( LAYER_NUM aLayer, CPOLYGONS_LIST& aOutlines )
 {
     // Number of segments to convert a circle to a polygon
-    const int       segcountforcircle   = 16;
+    const int       segcountforcircle   = 18;
     double          correctionFactor    = 1.0 / cos( M_PI / (segcountforcircle * 2) );
 
     // convert tracks and vias:

pcbnew/zones_convert_brd_items_to_polygons_with_Boost.cpp

@@ -199,9 +199,11 @@ void ZONE_CONTAINER::AddClearanceAreasPolygonsToPolysList( BOARD* aPcb )
      */
     MODULE dummymodule( aPcb );    // Creates a dummy parent
     D_PAD dummypad( &dummymodule );
-    D_PAD* nextpad;
+
     for( MODULE* module = aPcb->m_Modules;  module;  module = module->Next() )
     {
+        D_PAD* nextpad;
+
         for( D_PAD* pad = module->Pads(); pad != NULL; pad = nextpad )
         {
             nextpad = pad->Next();  // pad pointer can be modified by next code, so
@@ -228,7 +230,8 @@ void ZONE_CONTAINER::AddClearanceAreasPolygonsToPolysList( BOARD* aPcb )
                 pad = &dummypad;
             }
 
-            if( pad->GetNetCode() != GetNetCode() )
+            // Note: netcode <=0 means not connected item
+            if( ( pad->GetNetCode() != GetNetCode() ) || ( pad->GetNetCode() <= 0 ) )
             {
                 item_clearance   = pad->GetClearance() + margin;
                 item_boundingbox = pad->GetBoundingBox();
@@ -246,14 +249,15 @@ void ZONE_CONTAINER::AddClearanceAreasPolygonsToPolysList( BOARD* aPcb )
                 continue;
             }
 
-            int gap = zone_clearance;
-
             if( ( GetPadConnection( pad ) == PAD_NOT_IN_ZONE )
-                || ( GetNetCode() == 0 ) || ( pad->GetShape() == PAD_TRAPEZOID ) )
+                || ( pad->GetShape() == PAD_TRAPEZOID ) )
 
             // PAD_TRAPEZOID shapes are not in zones because they are used in microwave apps
             // and i think it is good that shapes are not changed by thermal pads or others
             {
+                int gap = zone_clearance;
+                int thermalGap = GetThermalReliefGap( pad );
+                gap = std::max( gap, thermalGap );
                 item_boundingbox = pad->GetBoundingBox();
 
                 if( item_boundingbox.Intersects( zone_boundingbox ) )