DO NOT MERGE:  Initial notifier component addition

Sending an early PR os that Stephanie and John can take a look, let me know what they think.

`mdn.notify` has two uses right now:

    *  `discover(parentElement)`: Finds notifications under a given parent (which would have been rendered with the initial server request), and adds close icon and other items accordingly.  Options are passed via separate `data-` attributes

    *  `growl(message, options)`:  Adds a growl message to the growl notification tray, options passed via said object.  

A `handle` is returned from creating the notification, with a few methods for updating the notification style/status, its message, and the ability to close the item.  You also (dangerously) get access to the element itself.

To Do:

    *  Decide if `mdn.Notifier` is where we want this to go.
    *  Apparently "icon-times" isn't available in our version of Font Awesome, so I'm using the trash can icon for deletion now.  Gross.  Need to either upgrade FA (may be difficult) or find a an image to use.
    *  Convert $.fn.mozNotifier uses to this new component.

Let me know what you think!
Since the notification is not an interactive UI element let's not track clicks this way (alternatively we can wire it to accept touch and keyboard iteration but I would rather not do all that work ;) . Links and buttons can be added in the body of the message.