[1.1] Subsurface

[Natha]

This aims to be a complete rewrite of the old mod (viewtopic.php?t=19178 by StanFear) to the new versions of Factorio.
Mod portal link: https://mods.factorio.com/mod/Subsurface

It is in a working state containing player, item and fluid elevators as well as power and circuit network transmission.

I would appreciate contributions on graphics and feature suggestions (some that go further than the original mod)