Custom Block & Item Support!

Added

• Item extends ItemStack
• PlayerEntity.getStackInMainHand
• PlayerEntity.getStackInOffHand
• Method extends Callable
• Function extends Callable
• Inventory class
• List toString
• ItemStack.init(item: Item, count: Integer) -> Null
• \uXXXX to strings
• String.fromUnicode(unicode: Integer) -> String
• GUI.onClose(player: PlayerEntity, gui: GUI) -> Null
• PlayerEntity.getEnderChestInventory() -> Inventory
• PlayerEntity.setEnderChestInventory(inventory: Inventory) -> Null
• Inventory constructor
• PlayerEntity.setInventory(inventory: Inventory) -> Null
• PlayerEntity.getInventory() -> Inventory
• NBTBoolean
• NBTCompound
• NBTElement
• NBTFloat
• NBTInteger
• NBTList
• NBTNull
• NBTString
• Casting
• start script tag
• nonnull access modifier
• Custom item/block support
• Items.register(item: Item) -> Item
• ItemSettings
• Blocks.register(block: Block) -> Block
• Blocks.registerWithItem(block: Block) -> Block
• BlockSettings