Add remove bundle to bevy_ecs commands (#579)

add remove bundle to bevy_ecs commands

crates/bevy_ecs/src/system/commands.rs

@@ -112,6 +112,23 @@ where
     }
 }
 
+pub(crate) struct Remove<T>
+where
+    T: Bundle + Send + Sync + 'static,
+{
+    entity: Entity,
+    phantom: PhantomData<T>,
+}
+
+impl<T> WorldWriter for Remove<T>
+where
+    T: Bundle + Send + Sync + 'static,
+{
+    fn write(self: Box<Self>, world: &mut World) {
+        world.remove::<T>(self.entity).unwrap();
+    }
+}
+
 pub trait ResourcesWriter: Send + Sync {
     fn write(self: Box<Self>, resources: &mut Resources);
 }
@@ -319,6 +336,16 @@ impl Commands {
         })
     }
 
+    pub fn remove<T>(&mut self, entity: Entity) -> &mut Self
+    where
+        T: Bundle + Send + Sync + 'static,
+    {
+        self.write_world(Remove::<T> {
+            entity,
+            phantom: PhantomData,
+        })
+    }
+
     pub fn set_entity_reserver(&self, entity_reserver: EntityReserver) {
         self.commands.lock().entity_reserver = Some(entity_reserver);
     }