Eeschema: add schematic sheet page number.

The groundwork has now been laid for per sheet instance data.  Initially
this only supports sheet page numbers but could be expanded to include
other per sheet instance information.

ADDED: Support for user defined schematic page numbers.

common/plotters/common_plot_functions.cpp

@@ -1,7 +1,7 @@
 /*
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
- * Copyright (C) 1992-2017 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2020 KiCad Developers, see AUTHORS.txt for contributors.
  *
  *
  * This program is free software; you can redistribute it and/or
@@ -55,8 +55,9 @@ wxString GetDefaultPlotExtension( PLOT_FORMAT aFormat )
 
 
 void PlotWorkSheet( PLOTTER* plotter, const PROJECT* aProject, const TITLE_BLOCK& aTitleBlock,
-                    const PAGE_INFO& aPageInfo, int aSheetNumber, int aNumberOfSheets,
-                    const wxString &aSheetDesc, const wxString &aFilename, COLOR4D aColor )
+                    const PAGE_INFO& aPageInfo, const wxString&  aSheetNumber, int aNumberOfSheets,
+                    const wxString& aSheetDesc, const wxString& aFilename, COLOR4D aColor,
+                    bool aIsFirstPage )
 {
     /* Note: Page sizes values are given in mils
      */
@@ -76,11 +77,12 @@ void PlotWorkSheet( PLOTTER* plotter, const PROJECT* aProject, const TITLE_BLOCK
     // Prepare plot parameters
     drawList.SetDefaultPenSize( PLOTTER::USE_DEFAULT_LINE_WIDTH );
     drawList.SetMilsToIUfactor( iusPerMil );
-    drawList.SetSheetNumber( aSheetNumber );
+    drawList.SetPageNumber( aSheetNumber );
     drawList.SetSheetCount( aNumberOfSheets );
     drawList.SetFileName( fn.GetFullName() );   // Print only the short filename
     drawList.SetSheetName( aSheetDesc );
     drawList.SetProject( aProject );
+    drawList.SetIsFirstPage( aIsFirstPage );
 
     drawList.BuildWorkSheetGraphicList( aPageInfo, aTitleBlock );