Refactor App Menu Architecture

New App Menu Architecture
-------------------------------------
Figure below show the new architecture for app menu. Please refer to this [document](https://github.com/pawanpoudel/Branded/blob/2f4b9896c0b68e297898a53057a09b52943bd72a/docs/app_menu/app_menu_architecture.md) to understand how the menu view is constructed and how the disabled features get removed from the menu.

![app_menu_architecture](https://cloud.githubusercontent.com/assets/115379/2812139/00ddc0c8-ce44-11e3-90cd-fe52e6e913cc.png)