Added natural gas grenades. :D

I added some gas grenades, mainly to combine with a few of the machines to allow some remote explosions. :D. (I forgot to add recipes, also I'm 13 and don't know how to add shaped recipes yet... :P)

--EDIT--
I fixed a couple of rendering problems I made, and they should work flawlessly now WITH localization, however, I have not added crafting recipes. I /might/ add one that makes a little sense, with glass or something, but I can't really think of anything myself.