Alternative Bastion Factory Cost - villagers

Alternative construction cost for https://github.com/ttk2/FactoryMod/pull/17

	**Bastion Factory** - 640 Obsidian, 128 Sticky Pistons, 64 Villager Spawn Eggs
	
	32 Bastions (Sponge) for 64 Redstone Blocks, 64 Lapis Blocks, 64 Emerald Blocks, 64 Coal Blocks
	
	Full repair costs 256 Emerald Blocks, 32 Sticky Pistons, 32 Villager Eggs

Instead of so much obsidian, which it has been pointed out is highly bottable, this requires a stack of villager eggs to set up and maintain. Being able to keep a factory therefore requires building and protecting a safe and stable village - a simulated "workforce".