Add Gas Conduits

Adds a new type of conduit that can transfer Mekanism gases. The conduit works similarly to the Pressurized Fluid Conduit.

A few things to note:
 - This includes the Mekanism API into the mod file. Mekanism does not use package-info files, though.
 - For some reason, Hydrogen can't be auto-outputted by Mekanism blocks into the conduits. I suspect this is a  bug on their side.
 - Every other gas seems to work just fine.