ItemsAdder support for the plugin MobArena

This plugin allows you to use ItemsAdder items in MobArena. When defining Items or Entities in the config, you can use the following syntax: itemsadder:<namespace>:<name> For example: itemsadder:iasurvival:firesword

When defining custom items ensure you follow the same procedure as you would for any other custom item.

itemsadder:<namespace>:<name>`

For example:

itemsadder:custom:ninja_skeleton