Crash when selecting a recipe on the Powder Mixer when cabinets not in place

[jorgebonafe]

If you have a Powder Mixer without the correctly placed Material or Elements cabinets, a crash happens with a nullpointerexception.

In the "drawGuiContainerBackgroundLayer", "drawGuiContainerForegroundLayer" and "drawScreen" methods of "UIPowderMixerController.java", the methods "getMaterialCabinet()" and "getElementsCabinet()" are called without a previous check to see if they exist.

[austinsupercar]

This happens to me too.