Fix both interfaces to raise the InterfaceClosed event when disposed rather than just when close is called, to ensure that subscribers to the event get a message when the windowing system is shut down, e.g. by the user and not programmatically. This fixes the bug with sounds playing after the interface is closed.
Change PonyAnimator.AllowManualControl to default to true so manual control is allowed outside of games.
Added a check in Pony to handle rebounding off containment area edges in the case where the mirrored image occupies a different region that means the image now extends out of zone. Since the pony is moving back into zone we will let them continue on the assumption they will shortly be back in zone anyway, rather than apply an in-zone destination immediately. Once back in zone or their movement is affected (and thus we are no longer sure if they'll end up back in zone) or they are totally out of zone (perhaps the allowed zone changed drastically and now they're wandering even further away) then we resume checking they are within zone.