GUI -- Update to memento format.

Change-Id: I99c579668b17014d4cdceb9ce5898c4ed49c5be4

@@ -10,6 +10,13 @@
       "",
       null
     ],
-    "props": {}
+    "props": {
+      "location": {
+        "type": "latlng",
+        "lat": 123.5,
+        "lng": 67.8
+      },
+      "anotherProp": "foobar"
+    }
   }
 }

+{
+  "event": "addDevice",
+  "payload": {
+    "id": "of:0000000000000003",
+    "type": "switch",
+    "online": true,
+    "labels": [
+      "of:0000000000000003",
+      "3",
+      "",
+      null
+    ],
+    "props": {
+      "location": {
+        "type": "latlng",
+        "lat": 123.5,
+        "lng": 67.8
+      },
+      "anotherProp": "foobar"
+    },
+    "metaUi": {
+      "xpc": 57.3,
+      "ypc": 24.86,
+      "and": "other properties the UI wishes to remember..."
+    }
+  }
+}

@@ -4,7 +4,11 @@
   "payload": {
     "id": "62:4F:65:BF:FF:B3/-1",
     "class": "host",
-    "x": 197,
-    "y": 177
+    "memento": {
+      "xpc": 57.3,
+      "ypc": 24.86,
+      "and": "other properties the UI wishes to remember..."
+    }
   }
 }
+

@@ -1154,16 +1154,18 @@
             d.fixed = true;
             d3.select(self).classed('fixed', true);
             if (config.useLiveData) {
-                tellServerCoords(d);
+                sendUpdateMeta(d);
             }
         }
 
-        function tellServerCoords(d) {
+        function sendUpdateMeta(d) {
             sendMessage('updateMeta', {
                 id: d.id,
                 'class': d.class,
+                'memento': {
                     x: Math.floor(d.x),
                     y: Math.floor(d.y)
+                }
             });
         }