adding overlap2d

README.md

@@ -97,6 +97,7 @@ Graphics
 * [ArrayPainter](http://www.arraypainter.com/) -  Array Painter is the easiest and fastest way to make 2D arrays ready for copy pasting into your own program.
 * [AutoTileGen](http://autotilegen.com/) - AutoTileGen is an automatic tileset generator for 2D game terrains.
 * [OGMO Editor](http://www.ogmoeditor.com/) - generic level editor.
+* [Overlap2D](http://overlap2d.com/) - a 2D level and UI editor with an engine agnostic philosophy.
 * [Mappy](http://tilemap.co.uk/mappy.php) - Free tilemap editor.
 * [Tiled](http://www.mapeditor.org/) - free, easy to use and flexible tile map editor.