Fix VR Mode

[brianpeiris]

VR mode doesn't work unless you set renderer.vr.enabled = true. Unfortunately, this also breaks OrbitControls in non-VR mode, so I hacked in a fix for that as well.

[emilyselwood]

This doesn't seem to break anything in non vr mode and the changes look entirely reasonable so I am going to merge this.

This is not the canonical copy of this repo at the moment. It is over at https://github.com/wselwood/orbcalc I'll sort out the transfer of it over there so don't worry, but do you mind if I list you as a contributor over there?

I'm planning to pull out the server part so this becomes a sub module kept here, I'm not sure what will happen to the history of this repo when that happens, so your contribution may get lost. Sorry if that happens.

[brianpeiris]

Sure, I'd be happy to be listed as a contributor. Thanks for the merge.