Added support for hoppers.
Fixed bug where blacklisted items could be dropped into blocks with inventories.
New Commands:
- /hopper help
- /hopper list
- /hopper <on/off>
- /hopper whitelist <on/off>
- /hopper <add/remove>
- /hopper name <on/off>
- /hopper name whitelist <on/off>
- /hopper name <add/remove>