Make sure focus_lost messages is received

Fixes #42

test/data/screens.collection

@@ -471,3 +471,66 @@ embedded_instances {
     z: 1.0
   }
 }
+embedded_instances {
+  id: "focus1"
+  data: "components {\n"
+  "  id: \"screen_proxy\"\n"
+  "  component: \"/monarch/screen_proxy.script\"\n"
+  "  position {\n"
+  "    x: 0.0\n"
+  "    y: 0.0\n"
+  "    z: 0.0\n"
+  "  }\n"
+  "  rotation {\n"
+  "    x: 0.0\n"
+  "    y: 0.0\n"
+  "    z: 0.0\n"
+  "    w: 1.0\n"
+  "  }\n"
+  "  properties {\n"
+  "    id: \"screen_id\"\n"
+  "    value: \"focus1\"\n"
+  "    type: PROPERTY_TYPE_HASH\n"
+  "  }\n"
+  "  properties {\n"
+  "    id: \"focus_url\"\n"
+  "    value: \"focus1:/go#focus1\"\n"
+  "    type: PROPERTY_TYPE_URL\n"
+  "  }\n"
+  "}\n"
+  "embedded_components {\n"
+  "  id: \"collectionproxy\"\n"
+  "  type: \"collectionproxy\"\n"
+  "  data: \"collection: \\\"/test/data/focus1.collection\\\"\\n"
+  "exclude: false\\n"
+  "\"\n"
+  "  position {\n"
+  "    x: 0.0\n"
+  "    y: 0.0\n"
+  "    z: 0.0\n"
+  "  }\n"
+  "  rotation {\n"
+  "    x: 0.0\n"
+  "    y: 0.0\n"
+  "    z: 0.0\n"
+  "    w: 1.0\n"
+  "  }\n"
+  "}\n"
+  ""
+  position {
+    x: 0.0
+    y: 0.0
+    z: 0.0
+  }
+  rotation {
+    x: 0.0
+    y: 0.0
+    z: 0.0
+    w: 1.0
+  }
+  scale3 {
+    x: 1.0
+    y: 1.0
+    z: 1.0
+  }
+}