Accept item as argument for tool or brush binding

WORLDEDIT-3348 - Reported by pez252

It would be helpful to accept an item name when binding a tool rather than requiring the item to currently be in your hand. This can be used by servers to give players kits of pre-bound tools.

I have attached ToolCommands.java with changes to make this work for commands defined there. It's probably not the best way, or most reliable (probably needs a rewrite by someone who knows java), but it is working on my test server.

It would be great if this could be added as a feature for tools or brushes that bind to an item.