implement interactions for link up/down flow up/down
setup controller interface. link up/down not currently working (or I'm not using them correctly)
diff --git a/web/ons-demo/css/skin.default.css b/web/ons-demo/css/skin.default.css
index 482cfbc..753fff3 100644
--- a/web/ons-demo/css/skin.default.css
+++ b/web/ons-demo/css/skin.default.css
@@ -92,6 +92,15 @@
 	background-color:#AAA;
 }
 
+circle.highlight {
+	stroke: rgba(255, 255, 255, .5);
+	stroke-width: 2px;
+}
+
+path {
+	pointer-events: none;
+}
+
 path.flow {
 	fill: none;
 	stroke-width: 3px;