notifications implementation (#34)

* wip: notifications

* wip: more notifications

* wip: add getter to proxy

* wip: add setter

* wip: add static getter and method

* wip: add event handlers

* wip: add doc

* wip: add api demo

js/enums/api.js

@@ -7,10 +7,23 @@ const cmds = keyMirror({
     open: null,
     registerLogger: null,
     setBadgeCount: null,
-    badgeDataUrl: null,
+    badgeDataUrl: null
+});
+
+const proxyCmds = keyMirror({
+    createObject: null,
+    addEvent: null,
+    removeEvent: null,
+    eventCallback: null,
+    invokeMethod: null,
+    invokeResult: null,
+    get: null,
+    getResult: null,
+    set: null
 });
 
 module.exports = {
     cmds: cmds,
+    proxyCmds: proxyCmds,
     apiName: 'symphony-api'
 }