changes & features:
- you can now save and quit mid-run, the game will also autosave every ~10 seconds
- poisonous cells are now immune to the effects of mutagenic poison
- made first biome smaller, with increased xp drops per enemy
- feeler cells now activate when adjacent cells are touched as well
- added some small passive creatures to the world

bugfixes:
- fixed some crashes
- fixed world generation error where biomes could be missing
- fixed compatibility issue on Windows 7