2251: merge BrigeElement *

BrigeElement derived from HtmlElement
2253: fixing
2261: errs!
2262_4: err1
2262_5 errr
2265: errs
2266
2267
2268
2264.3
2643.4
2269:
2264.4
2271
2272
2273
2274
Merge branch 'v1.7perf' into v1.7.2264.3

Conflicts:
	Source/HtmlRenderer.WinFormControls/Platform/HtmlContainerImpl.cs
	Source/HtmlRenderer/1_Boxes/1_BoxCore/CssLineBox.cs
	Source/HtmlRenderer/1_Boxes/4_Render/BordersDrawHandler.cs
	Source/HtmlRenderer/1_Boxes/6_OtherBoxes/ListItemHelper.cs
	Source/HtmlRenderer/BridgesAndBuilder/ContentTextSplitter.cs
	Source/HtmlRenderer/BridgesAndBuilder/RunListCreator.cs
2274
Merge branch 'v1.7.2264.3' into v1.7dev