Thursday tiny patch

This is a small bugfix patch addressing the following issues:

• Campaign - Greener pastures: Some savefiles in which the construction of the fargate has been started would crash the game upon loading. This should no longer happen.
• Campaign - Ghost in the Machine: The completion event would reappear after reloading a savefile where the megastructure was already reactivated. This should no longer happen.
• Visual: The "smudges" in the sector select screen background should no longer be visible. The galaxy is fine, please don't worry - these artifacts were actually part of the menu background which was dimly visible behind the galaxy.

This patch brings the version numbers up to "v1.3 (b1103)" on Windows and "v1.3 (b1104)" on Mac.