Added basic entity handling with copy and paste.

Paintings do not currently respawn properly, entity pastes cannot be undone yet, and schematics do not yet store entities
@celticminstrel needs to fix painting spawning

src/main/java/com/sk89q/worldedit/LocalWorld.java

@@ -501,4 +501,12 @@ public abstract class LocalWorld {
 
         return true;
     }
+
+    public LocalEntity[] getEntities(Region region) {
+        return new LocalEntity[0];
+    }
+
+    public int killEntities(LocalEntity... entities) {
+        return 0;
+    }
 }