Sluice can eat stacks of 1,2 or 3 items depending on available space.
Small performance optimization applied.
Fixed the issue with placement of ingot into the existing pile of other
metal kind. Small refactoring is applied.
Merge pull request #406 from ArtyomShegeda/master

Sluice can eat stacks of 1,2 or 3 items depending on available space. Small performance optimization applied. Fixed the issue with placement of ingot into the existing pile of other metal kind.