Added colors to signs: [Blue] means the shop is stocked and working, [Red] means the shop is out of stock (punch the sign or chest after restocking to change the color back to [Blue]), [Black] means the sign is not linked to a chest
Changed OP overriding permissions default to true (there is now an option in the config to disable this)
Fixed how servers without a permission plugin handles permissions
Now able to reuse signs when the chest is destroyed
playerIsOp SignShops (i.e. Admin shops) no longer count towards maximum allowed shops per player
