FastShop - Unique shop system v1.3.4

1. Made next/previous page not show if it's not available.
2. Fixed entering a category, you can't go back to the main menu.
3. Added /shop opencategory

1. You can now add permission to a category through ADMIN GUI.
2. Added per-item stock limits that refill over time.
3. Added dynamic supply & demand pricing.
4. Added timed sales and discount codes.
5. Added restock notifications when sold-out items come back.
6. Added per-item buy & sell permissions.
7. Added item search inside categories.
10. Added a transaction log.

1. Made it possible to change the vault currency prefix.

1. Added a %formatted_price% placeholder.

1. No longer items disappearing when you purchase items, false duplication flags.
2. Fixed the license check issue.

1. Added security checks, to make sure there won't be duplications using a GUI mod.

1. Fixed a few bugs in the admin GUI.

1. ADDED A NEW LICENSE SYSTEM, request a new license key first before adding the plugin.
2. Made the fun tool much better and nice looking, and can actually use it to fly around.
3.. Fixed the self-destruct not working on fireworks.
4. Fixed the normal firework tool being removed if used with elytra.
and more...