Progress on docking nodes

Docking nodes are now "complete". They're retextured, and rejigged to be compatible with Cobalt's BDB apollo/kane docking nodes.
The passive end of the probe/drogue set is the one that should go on the craft, if following real world expectations, but feel free to flip that around. It works either way.
Lots of testing by driving spaceframe mounted docking nodes around with rovers was required for this, as I kept stuff things up.