Adds stack size functionality to extraction module

This needs GUI work, but I thought I'd add this pull request so that whoever does GUI work does not have to do this.

The GUI work required is basically a button that is a max stack size, up to 64. I think it should be 64 - because as far as I know, Minecraft (and mods) try not to have stacks above 64.

@Dynious, @squeek502: I'm terrible at GUIs, so if someone wants to do the GUI that would be great. I'd probably learn a lot from that code. I probably can't do this GUI myself. Maybe in the future, if I explore this much more.