[0.9.2] Petroleum Gas icon wrong

[Malacodor]

Petroleum Gas consists of Propane and Butane (https://en.wikipedia.org/wiki/Liquefied_petroleum_gas) but the icon looks like Ethylene (https://en.wikipedia.org/wiki/Ethylene).

Edit: I suggest simply renaming petroleum gas to ethylene, since polyethylene (https://en.wikipedia.org/wiki/Polyethylene) is the most common plastic anyways.

[slpwnd]

Yes the icon is actually ethylen. I am not strictly against the change. Though petroleum gas seems to me easier to grab than ethylen. I am moving this to Ideas & Suggestions since it is not strictly speaking a bug.