GDM Face Browser

Discuss and agree changes to our default greeter.

 * input from hardy-theme discussion
 * default is a face-browser, allowing users to click on their name
 * shows face/image
 * maybe show name with face/image?
 * transitions between certain stages of the face-browser will be animated
 * OpenGL is used to allow smooth animations an off-load rendering from CPU
 * animations will use the concept of "implicit animation"
 * threshold of users for falling back to non-face greeter
 * ok-button on gdm non-face greeter (people don't think they can just hit ENTER)
 * username field hidden on face browser, start typing and it appears
 * gnome-about-me used to edit information (face/image)
 * try to integrate cheese and MeMaker with gnome-about-me (perhaps even ubiquity)
 * used to grab face-photos from webcam or use abstract images
 * provide a large set of high-quality stock images for users that don't want to use (don't have) webcam
 * or don't want to use the abstract avatar-images created with MeMaker
 * no session information except for already logged-in users
 * "screensaver-mode" for face-browser after x minutes of inactivity