Improved Mobs 1.15.0

• Add support for difficulty range config. See updated comment for the difficulty increase config
• Rewrite difficulty to use doubles instead of floats
• Rewrite Item AI handling
• Fix crossbow ai not working
• Fix projectile and explosion damage modifier
• Reduce size variation

For past versions see: https://github.com/Flemmli97/ImprovedMobs/blob/1.21/Changelog.md