Stacklands v1.5.0.21

Hey y'all! Some more bug fixes! [list] [*] Fixed a bug where pollution would pop out of landfill when there were multiple in the same frame [*] Fixed a bug where putting food with 0 food value into a hot pot would make the hot pot instantly fill [*] Fixed bug where food warehouse could cause an exception when it had less food value than its output [*] Made the max amount of cables, sewers and transport roads dynamic [*] Slightly improved the odds for getting rare cards from certain packs [*] Fixed a bug where robot society quest would trigger too late [*] Changed Have 5 Pets quest to Have 3 Pets [*] Airport no longer creates pollution every month [/list] Have fun! - Aran