Add SchemaVersion to reset themes to default on change

- Extract embedded ThemeSet type to new file
- Eliminate redundant SerializedTheme type
- Issue MatterHackers/MCCentral#4353
Toggle buttons missing dots

MatterControlLib/ApplicationView/Themes/IColorTheme.cs

@@ -36,9 +36,11 @@ namespace MatterHackers.MatterControl
 	public interface IColorTheme
 	{
 		string Name { get; }
-		Color DefaultColor { get; }
+
+		ThemeSet GetTheme(string mode);
 
 		ThemeSet GetTheme(string mode, Color accentColor);
+
 		IEnumerable<string> ThemeNames { get; }
 	}
 }