atlas importer for Tilemap (openfl >=4.0.2)

Now use Haxe 4!

Code based fairly inspired by tilelayer by elsassph

• SparrowTileset : (sparrow and starling format)
• SpriterTileset : (custom format for Spriter based on Sparrow that you can install for TexturePacker from here: https://github.com/loudoweb/SpriterHaxeEngine/tree/master/texturePackerExporter/spriterhaxeengine)

• get tile id from atlas. e.g: new Tile(tilesetEx.getImageID('knight'))
• use TileClip to animate your tiles. e.g : new TileClip('knight_', tilesetEx) and then use update() each frame

• SpriterJSONTileset : (official format for Spriter in json)
• ask for one or make a pull request