Bug Fixes and Menu Button Tweak

Tweaked the look of the selected button in the menus.
Fixed Infantry not being counted as dead when they explode from
landmines.
Fixed Infantry on Row Boats not being removed properly when the Row Boat
get's destroyed before it lands on the beach.
Fixed Ships and Row Boats not turning transparent when they become empty
if they were hit just as they became empty.
Row Boats now longer play the rowing animation while they are not
moving.