Output cubemap

[willbamford]

Would be great if this could also output a six-sided cubemap too

[spite]

Could be useful, although it's not really the purpose of this library.

May be a different library to download the rendertargets from a THREE.CubeCamera. What format would be useful: six images named accordingly, or a composed image in a cross-like layout?

[willbamford]

Either would be good, although separate images would maybe offer more flexibility.