[fixed] Exporting models with holes doesn't work.

[micheus]

Nova, the cause is the same as the one for the other bug you reported.
I took a look on it and I found I introduced it by fixing a bug related to hidden faces.

So, late today I'm going to replace the wings_we.beam into the bug fix zip files since this crash seems to be more critical to the hole one.

The complete fix is out of my possibilities, so we need to wait for Dan to check it and don't get the hidden faces bug anymore.