more ID functions

src/game.rs

@@ -350,11 +350,28 @@ impl ToString for Game {
 }
 
 impl Game {
+    // todo dedupe
+
     #[inline]
     pub fn tile_ids(&self) -> Vec<String> {
         self.tiles.iter().map(|tile| tile.id.clone()).collect()
     }
 
+    #[inline]
+    pub fn sprite_ids(&self) -> Vec<String> {
+        self.sprites.iter().map(|sprite| sprite.id.clone()).collect()
+    }
+
+    #[inline]
+    pub fn room_ids(&self) -> Vec<String> {
+        self.rooms.iter().map(|room| room.id.clone()).collect()
+    }
+
+    #[inline]
+    pub fn item_ids(&self) -> Vec<String> {
+        self.items.iter().map(|item| item.id.clone()).collect()
+    }
+
     /// first available tile ID.
     /// e.g. if current tile IDs are [0, 2, 3] the result will be `1`
     ///      if current tile IDs are [0, 1, 2] the result will be `3`