[Incomplete&Experimental] First pass of updating to 1.11.

Created by: Koward

Many changes happened and I have not tracked them all, plus Forge itself is still changing. One that's a bit tricky is that ItemStacks can't be null anymore, now we should check the "null" stack that is in a stack field of ItemStack. I'm trying to snipe them all but this will need a lot of testing. Of course mod integration is completely untouched since nobody is on 1.11 yet there's nothing we can do about that ATM.