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!
I would like to stop using RGBA values for colours with less than 0.8 alpha anywhere on MDN for contrast reasons.

Notifications specifically need solid colour backgrounds. If you don't want to use the stylus variables and functions from the requirements please (exact the hex values from here)[http://codepen.io/stephaniehobson/pen/CvuAa] and use those.