added knockback function to entity. Knockback is applied in one frame and if there would be collision, it is reduced until there is no collision anymore.
baby knocks player back.
hand knockback. Baby and hand knockback amount configurable in the interface.
skulls hopefully dont get stuck when spawned anymore. skulls do adhere to their limits now.
skullspawner should not spawn skulls which collide and thus never really start walking.
knockback is now spread out over knockbackSpread frames. (defaults to 4)
Merge branch 'feature/knockback' into develop