Changed "/vm" command permission to "vendingmachines.menu", also fixed a bug with "reload" command permissions.
Fixed an important bug when selling items to a VM.
Added a new message "SellerNoMoney" that is executed when you try selling to a VM and the owner of the vm doesn't have the money to buy the item.
Changed "vendingmachines.sell" permission to "vendingmachines.sellstocktomax" to make it less confusing. (if a player has this permission the stock of what they are selling is set to max automatically, use only for admins)