zShop - Advanced Inventory plugin

Add unstackable tag for ZSHOP_ITEM, allows you to choose the number of items to buy but not receive them stacked. Perfect for potions for example.

• Add inventory name for methods openBuy, openSell and openConfirm
• Add inventory name in ZSHOP_ITEM button, you can now specify the inventory for buy, sell and confirm

Added a system that will check the minimum version of zMenu the plugin needs

New version of the plugin, this time using the zMenu API. All information in the presentation page.

Fix 1.20 support