fixes:
- added new option in config.yml "keep-entity-uuid: false" to fix the error "Trying to add entity with duplicated UUID"
- fixed hopper dupe bug
- fixed balls being placed on ground if used with offhand
- fixed compatibility with "mod which automatically refills the itemstack in the player's hand" https://github.com/PluginBugs/Issues-PocketMobs/issues/3