Player: Improve interaction between players

On local multiplayer, other players shouldn't be an obstacle when
running. But still is nice to stand on another player for jumping
higher. It turns that making the player collision shape "one way" does
the trick.

components/player/player.tscn

@@ -38,3 +38,4 @@ animation = &"all"
 [node name="CollisionShape2D" type="CollisionShape2D" parent="."]
 position = Vector2(0, -46)
 shape = SubResource("CapsuleShape2D_7x5a4")
+one_way_collision = true