Rename getOwnerUUID to Tameable#getOwnerUniqueId for consistency

for the @kashike, thanks for adding a server diff to use this name!

Spigot-API-Patches/Tameable-getOwnerUniqueId-API.patch

@@ -0,0 +1,35 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <aikar@aikar.co>
+Date: Sat, 24 Feb 2018 00:55:52 -0500
+Subject: [PATCH] Tameable#getOwnerUniqueId API
+
+This is faster if all you need is the UUID, as .getOwner() will cause
+an OfflinePlayer to be loaded from disk.
+
+diff --git a/src/main/java/org/bukkit/entity/Tameable.java b/src/main/java/org/bukkit/entity/Tameable.java
+index 44497aa3..0987c1e8 100644
+--- a/src/main/java/org/bukkit/entity/Tameable.java
++++ b/src/main/java/org/bukkit/entity/Tameable.java
+@@ -0,0 +0,0 @@ public interface Tameable extends Entity {
+      */
+     public void setTamed(boolean tame);
+ 
++    // Paper start
++    /**
++     * Gets the owners UUID
++     *
++     * @return the owners UUID, or null if not owned
++     */
++    public java.util.UUID getOwnerUniqueId();
++    // Paper end
++
+     /**
+      * Gets the current owning AnimalTamer
+      *
++     * @see #getOwnerUniqueId() Recommended to use UUID version instead of this for performance.
++     * This method will cause OfflinePlayer to be loaded from disk if the owner is not online.
++     *
+      * @return the owning AnimalTamer, or null if not owned
+      */
+     public AnimalTamer getOwner();
+--