OpenGL ES 2.0 on iOS + Retina Display support for Stage3D

Hi!

I'm kinda new with Haxe / NME but I found a couple of small issues related to Stage3D on a Retina MBP and iOS. 

BTW, who is working on the OpenGL ES 2.0 support on mobile and how can I provide further help?

Thanks all for all this great work!