Improve javadoc in 26 files.

Addresses:
BUKKIT-1643, BUKKIT-1868, BUKKIT-1846, BUKKIT-2632, BUKKIT-3196,
BUKKIT-3187, BUKKIT-3198, BUKKIT-3200, BUKKIT-3201 and BUKKIT-3417.

By: feildmaster <admin@feildmaster.com>

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

@@ -20,7 +20,7 @@ public interface Entity extends Metadatable {
     /**
      * Gets the entity's current position
      *
-     * @return Location containing the position of this entity
+     * @return a new copy of Location containing the position of this entity
      */
     public Location getLocation();