1) Add 32 Cu Layers.

2) Change from legacy Cu stack to counting down from top=(F_Cu or 0).
   The old Cu stack required knowing the count of Cu layers to make
   sense of the layer number when converting to many exported file types.
   The new Cu stack is more commonly used, although ours still gives
   B_Cu a fixed number.
3) Introduce class LSET and enum LAYER_ID.
4) Change *.kicad_pcb file format version to 4 from 3.
5) Change fixed names Inner1_Cu-Inner14_Cu to In1_Cu-In30_Cu and their
   meanings are typically flipped.
6) Moved the #define LAYER_N_* stuff into legacy_plugin.cpp where they
   can die a quiet death, and switch to enum LAYER_ID symbols throughout.
7) Removed the LEGACY_PLUGIN::Save() and FootprintSave() functions.
   You will need to convert to the format immediately, *.kicad_pcb and
   *.kicad_mod (=pretty) since legacy format was never going to know
   about 32 Cu layers and additional technical layers and the reversed Cu
   stack.

common/common_plotSVG_functions.cpp

@@ -420,14 +420,14 @@ void SVG_PLOTTER::PlotPoly( const std::vector<wxPoint>& aCornerList,
 
     switch( aFill )
     {
-        case NO_FILL:
-            fprintf( outputFile, "<polyline fill=\"none;\"\n" );
-            break;
+    case NO_FILL:
+        fprintf( outputFile, "<polyline fill=\"none;\"\n" );
+        break;
 
-        case FILLED_WITH_BG_BODYCOLOR:
-        case FILLED_SHAPE:
-            fprintf( outputFile, "<polyline style=\"fill-rule:evenodd;\"\n" );
-            break;
+    case FILLED_WITH_BG_BODYCOLOR:
+    case FILLED_SHAPE:
+        fprintf( outputFile, "<polyline style=\"fill-rule:evenodd;\"\n" );
+        break;
     }
 
     DPOINT pos = userToDeviceCoordinates( aCornerList[0] );