Upgraded to Haxe 3 and OpenFL

At least it worked for me with target neko and target flash. I will do further testing when possible.

Also, maybe there are developers that need the Haxe 2 NME version. Regarding such case, maybe the best option would be to include a link to this fork in your readme, so those looking for the Haxe 3 OpenFL version can avoid some code ugrading/fixing.

Thanks for StablexNet, it's being really useful! :)