Refactory the Tile/Block Entity Rendererers

[ramou]

• [x] Determine if the association between renderer and entity happens automatically with subclasses: The answer seems to be no, you have to do it explicitly
• [ ] Split the EntityRenderer into a WoodEntityRendere and a GoldEntityRenderer (or something like that) to do away with the instanceof nonsense
• [ ] Register the Tile/Block Entities with the specific renderers