Hi all!
This update brings some much needed changes that have been highly requested. I still plan on adding multi-language support but it's very time consuming and I've been very busy as of late, I'm in my senior year of college now. That will likely be the next update, version 1.3.1. There's also a good chance that version 1.3.1 will be the final update of the free version of this plugin. I have a lot of ideas in the works and if I continue further with this plugin I need some monetary compensation for it, especially since I have plans to do some web-developing for features like a breeding calculator and displaying family trees, and hosting web servers costs money. So stay tuned for more! Hopefully I can working on that soon, but nothing's been set in stone yet.

Changelog:

• Applied the features of this plugin to all horse-like animals: donkeys, mules, skeleton horses, zombie horses, and... llamas!
  • Note: This greatly buffs mules since they can now be effectively bred to the same stat levels of horses. However, horses are still very valuable because they have higher starting stats, are the only creatures whom the ownership protection feature affects since they're the only ones that can wear armor, and I also set it so that only horses are affected by whistles. I may change this in the future to make whistles also work on mules.
• Added permissions!
  • horseo.claimWild:
    • description: Grants you permission to claim wild horses (requires ownership to be enabled in config)
    • default: true
  • horseo.claimOwned:
    • description: Grants you permission to claim other owned horses using their deeds (requires ownership to be enabled in config)
    • default: true
  • horseo.reload:
    • description: Allows an admin to refresh HorseOverhaul's configuration
    • default: op
  • horseo.interactAll:
    • description: Allows you to ride/interact with any horse regardless of ownership
    • default: false
• added a reload command
  • users with the horseo.reload permission can reload the plugin's config by typing /horseo reload
• rewrote the config to be more legible. Wish I could've done better but I had a hard time working with spigot's config integration
  • your config is now stored in settings.yml rather than config.yml. Be sure to set your preferences after updating, then use the /horseo reload command
• More informative messages while using a whistle
  
• removed the drop horse gear feature, it was functionally redundant
• removed option to turn off auto gear equip, it was pointless
• updated the demonstration video