[Bleeding] Added Potions API. Fixes BUKKIT-389

By: fullwall <fullwall@optusnet.com>

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

@@ -1,8 +1,15 @@
 package org.bukkit.entity;
 
+import java.util.Collection;
+
+import org.bukkit.potion.PotionEffect;
+
 /**
  * Represents a thrown potion bottle
  */
 public interface ThrownPotion extends Projectile {
-
+    /**
+     * Returns the effects that are applied by this potion.
+     */
+    public Collection<PotionEffect> getEffects();
 }