Adding .pex support for AssetManager class

Hi,
i've added .pex support without that AssetManager needs to know the Particle-System extension.
In practice just put your particle assets to assets/particles/{0}x directories and enque it with
assets.enqueue(...,
			  appDir.resolvePath(formatString("particles/{0}x", scaleFactor))
			  );

In the class that wants to add a particle extension just write
_fullExplosion = new PDParticleSystem(Game.assets.getParticleConfig("YourExplosion"), Game.assets.getTexture("YourExplosion"));
addChild(_fullExplosion);

and it works. No embedding of textures or .pex files needed anymore.

I hope that you can use it.
Best regards
Valentin