Improve output: distinguish between failed assertions (failures) and unexpected exceptions (errors), and print a filtered stack trace for any exception.

webapp/web/src/widget/templates/Tree.css

@@ -0,0 +1,29 @@
+.dojoTree {
+	font: caption;
+	font-size: 11px;
+	font-weight: normal;
+	overflow: auto;
+}
+
+.dojoTreeNodeLabel {
+	padding: 1px 2px;
+	color: WindowText;
+	cursor: default;
+}
+
+.dojoTreeNodeLabel:hover {
+	text-decoration: underline;
+}
+
+.dojoTreeNodeLabelSelected {
+	background-color: Highlight;
+	color: HighlightText;
+}
+
+.dojoTree div {
+	white-space: nowrap;
+}
+
+.dojoTree img {
+	vertical-align: middle;
+}