Implement a Javascript library to enable masking regions of an image and fetching the mask boundaries.

You will be provided with a stubbed Javascript class that defines the public API.  You will also be provided with a demo.html file that uses the library.  We will use this demo file to review the work.

Acceptance criteria:

 General:
 - Can add a new mask (newMask function)
 - Can programmatically add a mask (addMask function)
 - Can delete a mask by clicking a 'x' or using a hotkey
 - Can get a list of the masks (getMasks function)
 - Can drag masks around
 - Can resize masks by dragging borders or corners of mask
 - Works on IE6, IE7, IE8, FF3, Safari 4, Chrome
 - Include/Exclude opacity:
   - When mode==exclude, masked regions should have opacity=50%
   - When mode==include, non-masked regions should have opacity=50%

 Crop boundaries and image scaling:
 - addMask and getMasks should accept and return coordinates based on the image's full size
 - library should compensate for scaling.  Example:
     - paris-train.jpg image is 2304x1728
     - demo.html displays the image with width=600 (26% of original size)
     - if addMask(100, 100, 500, 200) is called, these should be scaled so that the box is
       placed at (26, 26, 130, 52) on the scaled image.

 Technical:
 - No other dependencies exist besides jQuery 1.3.2
 - Code does not use any global variables
 - Code uses jQuery() instead of $() global