[Bleeding] Added Potions API. Fixes BUKKIT-389

By: fullwall <fullwall@optusnet.com>

paper-api/src/main/java/org/bukkit/potion/PotionBrewer.java

@@ -0,0 +1,31 @@
+package org.bukkit.potion;
+
+import java.util.Collection;
+
+/**
+ * Represents a brewer that can create {@link PotionEffect}s.
+ */
+public interface PotionBrewer {
+    /**
+     * Creates a {@link PotionEffect} from the given {@link PotionEffectType},
+     * applying duration modifiers and checks.
+     *
+     * @param potion
+     *            The type of potion
+     * @param duration
+     *            The duration in ticks
+     * @param amplifier
+     *            The amplifier of the effect
+     */
+    public PotionEffect createEffect(PotionEffectType potion, int duration, int amplifier);
+
+    /**
+     * Returns a collection of {@link PotionEffect} that would be applied from a
+     * potion with the given data value.
+     *
+     * @param damage
+     *            The data value of the potion
+     * @return
+     */
+    public Collection<PotionEffect> getEffectsFromDamage(int damage);
+}