Add API for getting and setting Skeleton and Zombie types. Fixes BUKKIT-2818

By: James Clarke <jamesrtclarke@me.com>

paper-api/src/main/java/org/bukkit/entity/Zombie.java

@@ -3,4 +3,32 @@ package org.bukkit.entity;
 /**
  * Represents a Zombie.
  */
-public interface Zombie extends Monster {}
+public interface Zombie extends Monster {
+    /**
+     * Gets whether the zombie is a baby
+     *
+     * @return Whether the zombie is a baby
+     */
+    public boolean isBaby();
+
+    /**
+     * Sets whether the zombie is a baby
+     *
+     * @param flag Whether the zombie is a baby
+     */
+    public void setBaby(boolean flag);
+
+    /**
+     * Gets whether the zombie is a villager
+     *
+     * @return Whether the zombie is a villager
+     */
+    public boolean isVillager();
+
+    /**
+     * Sets whether the zombie is a villager
+     *
+     * @param flag Whether the zombie is a villager
+     */
+    public void setVillager(boolean flag);
+}