Support for rounded rectangles

[urmilparikh]

They do not get un-highlighted correctly when another node/path is selected.

digraph {
	bgcolor="#2e3e56"
	pad="0.5"
	node [shape="rectangle", width="0.6", style="rounded, filled", fillcolor="#edad56", color="#edad56", penwidth="2", label=""]
	edge [color="#fcfcfc", fontcolor="#fcfcfc", penwidth="2", fontname="helvetica Neue Ultra Light"]
	rankdir=LR;
	n61 [fillcolor="#BDE5F2", color="#BDE5F2", label="Test"];
	n62 [fillcolor="#BDE5F2", color="#BDE5F2", label="Edge"];
	n63 [fillcolor="#BDE5F2", color="#BDE5F2", label="Another"];
	n64 [fillcolor="#BDE5F2", color="#BDE5F2", label="Final"];
	n61 -> n63 [label=""];
	n63 -> n64 [label="label"];
	n62 -> n64 [label="label"];
}