WebGL example doesn't render (black screen)

[darknoon]

Steps to repro:

• Download latest master
• Unzip http://phoboslab.org/files/Ejecta-ThreeJS-CubeMap.zip as App/
• Run

Expected result: Demo renders

Actual result: Black screen

Discussion: It appears that the framebuffer is getting unbound in -[EJCanvasContextWebGLScreen resizeToWidth:height:]

Fixing it seems to be a touch involved, but I started messing around with keeping EJ_WEBGL_DEFAULT_RENDERBUFFER set in boundRenderbuffer and the same for the framebuffer to try to have it get fixed in -prepare, but I'm not familiar with all of the state management code here.

[phoboslab]

Thanks!