2100: BridgeElement***
2101: BoxSpec?
2102: CssBoxTemplate

delete BoxSpec
2103: attempt to separate CssBox build state
2104: BridgeHtmlNode,Element,Text
2015: BoxSpec
Merge branch '1.7dev' into v1.7

Conflicts:
	Source/Demo/DemoForm.cs
	Source/Demo/DevForm.cs
	Source/Demo/Samples/00.Intro.htm
	Source/Demo/Samples/03.Tables.htm
	Source/HtmlRenderer/0_Boxes/0_BoxCore/CssBox.cs
	Source/HtmlRenderer/0_Boxes/0_BoxCore/CssBoxBase.cs
	Source/HtmlRenderer/0_Boxes/0_BoxCore/CssBox_Fields.cs
	Source/HtmlRenderer/0_Boxes/0_BoxCore/CssBox_InheritAndClone.cs
	Source/HtmlRenderer/0_Boxes/0_BoxCore/CssBox_Paint.cs
	Source/HtmlRenderer/0_Boxes/0_BoxCore/CssLineBox.cs
	Source/HtmlRenderer/0_Boxes/3_Layout/CssLayoutEngine.cs
	Source/HtmlRenderer/0_Boxes/4_Render/BordersDrawHandler.cs
	Source/HtmlRenderer/BridgesAndBuilder/BoxModelBuilder.cs
	Source/HtmlRenderer/BridgesAndBuilder/BoxModelBuilder_Corrector.cs
2118: ** Separate CssBox and Props

1. still error!
2. CssBox store css properties in CssSpec
    CssSpec can be shared between CssBox
2119
2120: developing ...
2105
2107:err
2108:err
2118
2120
Merge branch '1.7.2105' into 1.7dev
2105.3
2105.4
2105.5
2105.6