Added slides.

Signed-off-by: Gianni Valdambrini <aleister@develer.com>
Removed unused signals.

Signed-off-by: Gianni Valdambrini <aleister@develer.com>
Moved the container for slides into a separate component.
Reworked the mouse/keyboard handlers.
Implemented a kind of virtual functions to allow slides to reimplement
the normal behavior to go to the next/prev slide and used it for either
the EndSlide and the LetsTalkSlide.

Signed-off-by: Gianni Valdambrini <aleister@develer.com>
Added a slide for webkit (and do other small stuff).

Signed-off-by: Gianni Valdambrini <aleister@develer.com>