[Gzz] Depth bug not fixed

[Benja Fallenstein]

The depth bug isn't fixed, actually (tho Tuomas pointed out another 
one). And stencildepth.py actually shows it: the first coordset has 
depth 10, the second coordset has depth 20, yet the second is shown 
*above* the first one! It seems that drawing order is determined by the 
order the things are placed into the vobmap, i.e. it seems that the 
depth test still isn't done properly.

Committed a change to show: left side is correct, right side is wrong.

- Benja