Added new origin: Stepping Stone.

EDAI fixes to better cater for lithoids that don't need food.
Stockpiling modifiers should not be duplicated on AI planets, for realz this time.
Fixes to a scripted trigger library that lost some braces.
Potential fix for Mega City decision not appearing on planets that end up with cities rather than mega-cities after a planet-class conversion.

• Left beta.
  
• Improved Auto-resettle. If resettling a pop would result in a building slot being locked, auto-resettle does nothing. It will start resettling pops again once population increases to a point where a building slot will not be locked due to pop reduction.
  
• Improved Employment Review a little. You may still need to toggle favourites on strata after using it, to force more promotions.
  
• Made certain trait/job weights a lot stronger, and added AlphaMod's new traits into the job assessment weights.
  
• Added new colony specialism, Internment World. Yes, gulags are back! Its use is heavily restricted, but needless to say that enslavers of primitives will get a lot of use out of it.
  
• Gate-makers AP is back!
  
• Started an art pass, beginning with resource icons. Expect some inconsistency across some art elements until I get to them.
  
• Re-worked modifiers from Waste Policy options.

• Stockpiling modifiers shouldn't be duplicated on AI planets.
  
• Favoured pop modifier should not be added to pops that already have it.
  
• Resource silos can be upgraded. Upgrades unlocked by tech.