Added entity.get/setMomentum

By: Dinnerbone <dinnerbone@dinnerbone.com>

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

@@ -4,6 +4,7 @@ package org.bukkit.entity;
 import org.bukkit.Location;
 import org.bukkit.Server;
 import org.bukkit.World;
+import org.bukkit.util.Vector;
 
 /**
  * Represents a base entity in the world
@@ -16,6 +17,20 @@ public interface Entity {
      */
     public Location getLocation();
 
+    /**
+     * Gets this entity's current momentum
+     *
+     * @return Current travelling momentum of this entity
+     */
+    public Vector getMomentum();
+
+    /**
+     * Sets this entity's momentum
+     *
+     * @param vector New momentum to travel with
+     */
+    public void setMomentum(Vector vector);
+
     /**
      * Gets the current world this entity resides in
      *