Already done for other blocks, should do it for crafting tables, too.

Done and done!

Had to undo the work from this due to a bug with smithing tables (see #371 ). I'm thinking of using a user-customizable whitelist in the future, but until then, this issue is back open.

I should use tags for this. Great system already in the game. I can internally keep a list of all crafting tables I know are supported, and it should let authors add their own through the vanilla tag system (will have to write a wiki article for that).