Version 0.5.2

You know the drill - this timelapse video shows off the features well.

Changes:

1. War exhaustion is no longer a value.
2. Stability is no longer a value, but instead a civilization has a tiny chance to collapse at any time.
3. Gaining technology is now not based on progress, but is random.
4. Made it possible to zoom in and out with the keyboard by holding the keys down again.
5. Did away with "Strengths" for Civilizations.
6. Distance from capital no longer affects supply