Automatically adding a SkelRoot

[koen-v]

Hello all,
I have a lot of scenes where the rig and the model dont share a parent, so the default exporter will fail. In my local build of the plugin, I added some code to convert the -parentScope from a scope to a SkelRoot, this allows scenes without a shared root to still be exported.

I have not tested this in all scenarios, but it seems to work in my setup. Before I port this from 0.9.0 to the head and submit a pull request, I was curious if there is any interest in this from others.

thanks,
Koen