Bow sprite

Adding the missing sprites for the Wooden bow. As reported in issue #40, I propose to delay the quiver issue a bit, perhaps use it with stronger bows only (especially when we make a longbow, this could also be carried on the back then, when someone solves the sprite problem (https://forums.themanaworld.org/viewtopic.php?f=36&t=19755&p=153196&hilit=quiver#p153196).