Reverts Cael's retard flailing.  Do not fuck with zone sharing ratios unless you know what you are doing, as air movement then becomes quite chaotic and derpy.  Should fix some issues with ZAS.
Fixed fire.
Makes liquid fuel cleanable again.  Got removed in last commit since all that was done was revert Cael's changes.
Merge pull request #2621 from SkyMarshal/bugfixes

Reverts Cael's retard flailing.  Do not fuck with zone sharing ratios...  Also: Fixed fire.