Quad from int -> float64

[fjmk]

dom.GetBoxModel returns floats sometimes
Error: json: cannot unmarshal number 1143.96875 into Go struct field BoxModel.content of type int

Some code to test is (added to your screenshot example):

			// Get document nodeID
			var nodeID, elementID dom.NodeID
			if node := <-tab.DOM().GetDocument(&dom.GetDocumentParams{-1, false}); node.Err != nil {
				panic(node.Err)
			} else {
				nodeID = node.Root.NodeID
			}
			// get elementID
			if element := <-tab.DOM().QuerySelector(&dom.QuerySelectorParams{nodeID, "#fsr"}); element.Err != nil && element.NodeID != 0 {
				panic(element.Err)
			} else {
				elementID = element.NodeID
			}
			
			var model *dom.BoxModel
			if boxModel := <-tab.DOM().GetBoxModel(&dom.GetBoxModelParams{elementID, 0, ""}); boxModel.Err != nil {
				panic(boxModel.Err)
			} else {
				model = boxModel.Model
			}

I am not sure if this affects other code and/or tests in this library.