#64 add list to menu

This doesn't have the updated README yet. 
This is an idea I came up, therefore it will still be for further review and feedback.

Do not merge this pull request yet, unless otherwise approved by @karelOK.

To add custom menus that will redirect to a virtual page, it will still be done as normal.

Adding custom menus that will redirect to a virtual page is the same as adding custom menus that redirects to a specific url.

![adminmenu](https://cloud.githubusercontent.com/assets/2107541/3241122/d2fc42ac-f138-11e3-93e8-2839c7b45d6d.jpg)

To make a specific menu redirect to a virtual page, the value in the `url` field should either be `http://*`, `/*`, or `*`.

![links](https://cloud.githubusercontent.com/assets/2107541/3241141/1fd5b00e-f139-11e3-9da3-e1b83434a443.jpg)

You can rearrange the order of the menu, or make it a child (or grand child) of another menu just like the way it does normally.

![menu_struct](https://cloud.githubusercontent.com/assets/2107541/3241145/3f39561c-f139-11e3-97dc-670129e6b057.jpg)

The plugin will then convert the urls (`http://*`, `/*`, or `*`) to a virtual url.

![menu](https://cloud.githubusercontent.com/assets/2107541/3241182/c196ee94-f139-11e3-948e-2efe11504355.jpg)