Villager Tweaks

- Updated to Minecraft 1.8;
- Current Features:
    - Zombie Villagers may drop emeralds (15% chance + 5% per looting level);
    - Regular zombies may drop feathers (5% chance);
    - Villagers can be named by sneaking + right-clicking on them with a name tag;
- Removed requiring player kill to drop emeralds, the chance is low enough;
- Removed Witches spawning on swamps since vanilla added that a while ago;