Minor cosmetic additions and fixes around the sub.

Fixed the Hellion's neutral ballast level for Rising Tide update.*

Adjusted wiring in the Hellion. An unintended effect of this is that the lower airlock can now be kept open without sinking the hellion completely, as the pump receives enough power to outpace the flooding for the most part.

*(Hellion had to have its neutral level dropped by half, for some reason only Jupiter knows, from 0.2400 to 0.1182. Anything higher and it sinks like a rock in the most recent update.)

Improved AI waypoints on the bridge stairs.

Fixed a pipe in Aft Section having the same depth as an overlapping decoration which made it look weird.

Fixed ventilation background decoration in Fabrication accidentally being set to Hidden In-game.

Fixed hologram in Engine Room having the wrong colour.