Output size greater than 1 for Kilns

[Rundas01]

Kilns could be used as a primitive furnace equivalent (or even completly substitute the fueled furnace). For that, it would be nice to have a larger output size than 1. In the attached screenshots you can see that I have added some ore smelting recipe to the Kiln which is shown correctly in JEI but yields only 1 output because of the size limit.