want to be able to drain empty bucket from the [furnace out] sign

[mc-yuu2132]

First of all, thanks for a very nice plugin! These features are very hopeful.

When using [furnace out] sign, we can drain the finished recipe from the furnace to the chest cart, but when we use a lava bucket for fuel, the bucket is not drained after use, making it very difficult to use in this point.

Please add the functions to drain used fuel!