Villager Optimizer

This mod (in its final form) will optimize villagers very seriously. In the very short period of time I'll add 4 types of villager optimization utils:

1. You can name a villager (using a name tag) _trader_ (without commas) and he won't move, won't use its AI but still will be able to trade (good for big trade halls)
2. You can name a villager (using a name tag) _ironman_ (without commas) and he won't move, won't use its AI but still will be able to produce iron golems (good for big farms of iron)
3. You can name a villager (using a name tag) _walker_ (without commas) and he will only be able to walk around (better for decorations (if you wold like to add some life to your world) than usual villagers, because walkers have simplified AI)
4. You can name a villager (using a name tag) _farmer_ (without commas) and he will only be able to rise crops (better for big farms)