A Shadowbox "player" is a class that is used specifically for displaying a
particular medium. For example, an image player is included for displaying
images, a QuickTime player is included for playing QuickTime movies, etc.

All players should implement the same interface. This makes it possible for the
Shadowbox class to know what methods to call and properties to check on player
objects.

The interface is described here, with some simple explanations of how each
method and/or property is to be used.

METHOD/PROPERTY     DESCRIPTION

height              (Number) The height of the object (in pixels)
width               (Number) The width of the object (in pixels)
ready               (optional, Boolean) True if the content is ready to be
                    loaded, false otherwise. Useful when the script should wait
                    until the content loads before proceeding (see below)
resizable           (optional, Boolean) True if the content can be dynamically
                    resized by the script (e.g. images, but not most movie
                    formats)
append()            Appends this object to the DOM
remove()            Removes this object from the DOM
onLoad()            (optional) Called after the content is loaded and the
                    loading layer is hidden
onWindowResize()    (optional) Called when the window is resized

If the ready property is set to false, the script will wait until it is set true
before proceeding to call the onReady callback. This property should be changed
in some callback function within the player class itself.

In this case, the object's height and width do not need to be made available
immediately (because they may not initially be known). However, in the same
callback, the height and width should be set. See the Shadowbox.img class (in
shadowbox-img.js) for an example of this behavior.
