Port tilemap-test to TiledMap

Easy enough, just need to disable the default tile as this example doesn't want the background

tilemap-test/assets.yml

@@ -3,3 +3,5 @@ assets.cpp:
     name: asset_platformer
   ../assets/tilemap-test.tmx:
     name: asset_tilemap
+    output_struct: true
+    empty_tile: 256 # we don't want an empty tile

tilemap-test/tilemap-test.cpp

@@ -8,14 +8,14 @@
 
 using namespace blit;
 
-TileMap* environment;
+TiledMap *environment;
 
 /* setup */
 void init() {
   blit::set_screen_mode(ScreenMode::lores);
 
   screen.sprites = Surface::load(asset_platformer);
-  environment = new TileMap((uint8_t*)asset_tilemap, nullptr, Size(64, 64), screen.sprites);
+  environment = new TiledMap(asset_tilemap, screen.sprites, LAYER_TRANSFORMS);
 }