Change return type of getMedia in MediaContent to List<Media>

[markpollack]

from

public interface MediaContent extends Content {

	/**
	 * Get the media associated with the content.
	 */
	Collection<Media> getMedia();

}

to

public interface MediaContent extends Content {

	/**
	 * Get the media associated with the content.
	 */
	List<Media> getMedia();

}