Patch 1.4.3b

Quick patch, primarily to fix the population freezing at 1.

• When hitting 150k population most systems would stop to work. It was impossible to unlock the new school building. [reported by YRMP]
  
• Fixed zoning cubes turning red even when construction is possible in the area.
  
• Disabled UI button selection with WASD.
  
• Improved visibility of the pollution heatmap.
  
• Doubled the maximum limit of pollution possible on a given tile.
  
• Pollution propagation distance decreased by 20%.