Quick fix for the material synthesizer

Created by: unid15

spawning plasma glass while ordinary glass is present in the module will no longer merge the two together when spawning more material than you can carry (like 50 sheets when you have 2 in the module) will no longer drop the entire new stack on the ground, but instead it will add as much as possible to the module (i.e. add 48 sheets and drop the remaining 2)