Spacecraft updates by DaveBowman2001

[SevenSpheres]

Spacecraft updates by @DaveBowman2001, since he's apparently unable to make a pull request himself.

• New ISS model
• Parent bodies of Cassini, Huygens, and Galileo changed to fix shadowing issues
• Orientation of Huygens with Cassini fixed; closes #77
• Orientation and trajectory of Galileo Probe fixed; closes #76
• Data updates for Mars Odyssey and MGS

[DaveBowman2001]

Thank you @SevenSpheres and @Askaniy !