Attempt to restore vents, scrubbers and pipes around central.
Restores lost vents and scrubbers around central hallway and broken pipes, caused by previous merge.

Expands central hallway area where necessary to ensure that, for example, air alarms in the captain's office won't lower emergency shutters in the hallway.
Sorts some odd lone emergency shutters in the brig.
More overwritten pipe-changes detected. Central area, r-wall move.
Misc. Research had a weird old tile, causing yet another pipe-disconnect.
Merge pull request #4939 from PsiOmegaDelta/AllOverAgain

Map merge fixes + more