Couple bug fixes

Placing empty tray in oven no longer causes crash
Player gets burned when standing in front of open hot oven regardless of
tray status
Fixed brittle limestone to smooth smelting recipe
Fixed tray render for small items/blocks based on tray slot location
Ores now don't smelt if the door to the oven is open
Merge branch 'master' of https://github.com/CyanideX/Electrodynamics