Text attributes object improvements.

* Add compare method to COLOR4D object.
* Add unit test to validate COLOR4D comparison method.
* Add missing color test in text attribute comparison method.
* Add unit test for text attribute object.
* Remove unnecessary headers from text attribute header.
* Move text attribute code into separate source file.

eeschema/sch_plotter.cpp

@@ -4,7 +4,7 @@
  * Copyright (C) 1992-2018 Jean-Pierre Charras jp.charras at wanadoo.fr
  * Copyright (C) 1992-2010 Lorenzo Marcantonio
  * Copyright (C) 2011 Wayne Stambaugh <[email protected]>
- * Copyright (C) 1992-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 1992-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -24,6 +24,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
+#include <wx/log.h>
 #include <common.h>
 #include <sch_plotter.h>
 #include <locale_io.h>
@@ -1069,4 +1070,4 @@ void SCH_PLOTTER::Plot( PLOT_FORMAT aPlotFormat, const SCH_PLOT_SETTINGS& aPlotS
     case PLOT_FORMAT::SVG: createSVGFiles( aPlotSettings, aRenderSettings, aReporter ); break;
     case PLOT_FORMAT::HPGL: createHPGLFiles( aPlotSettings, aRenderSettings, aReporter ); break;
     }
-}
+}