AuctionHousePlugin

Changelog:

• added simple transaction logging [date, buyer, seller, item-name, amount, price, is-BID-auction]
• added [/ah help]
• auction master npc can't be picked up by using the ClickVillagers plugin anymore
• NPCs can't be removed by players who are only in creative mode anymore. You also need the moderator permission to do that.
• to summon a display, the surrounding blocks must now be air
• made the item displays more customizable in messages.yml
• added %price-trim% as a placeholder in the messages.yml file if you want to display "3.2K coins" instead of "3,200 coins"
• fixed an update problem from early versions of the plugin