Structure entity rotation is handled incorrectly

When an entity is loaded from a structure, the rotation and mirroring of the structure are not applied to the entity correctly. As for mirroring, the code in Entity.class mirrors front-back as if it was left-right and vis versa. For rotation, in Template.class entities are rotated in the opposite direction of the structure's rotation. So a structure rotated 90 degrees has the entity rotated -90 degrees, and 270 turns into -270.