Fix assertion when attempting to dock...

Fix assertion when attempting to dock whilst you're also trying to leave (#2239).

This does a few things:
* stops you even asking to dock or get clearance whilst docking/undocking,
* attempts to handle cases where it somehow gets past that,
* fixes the doors not animating after loading a game mid-undock,
 * but doesn't fix the bad positioning of the ship,
* dumps the save game version to 66,
* adds a bad save game version string and exception,
* removes the UNUSED num_docking_ports number - it was deprecated an alpha ago anyway,
* attempts to deal with station initialisation after a Load better,
 * this needs some attention and fixup - InitStation seems to be serving dual purposes.

I think that's it.

Andy