New system for CO2 asphixyation

Too much CO2 now makes you slowly gain oxyloss instead of making you
fall unconscious immediately and quickly killing you after 30 seconds.
Completed unfinished species.breath_type switch
Adjusts co2 warning frequencies
Fixes missing 'else'
C02 -> carbon_dioxide

Renamed carbon dioxide breathing type string to hopefully prevent
confusion in the future.
Merge pull request #5083 from mwerezak/co2

New System for CO2 Asphixyation
Vending machines can now be unanchored
Adds ability to have airlock wires randomized

Adds a secured_wires var to airlocks that may be set through mapping. If
not set to 0, the airlock's wires will be randomized for that airlock,
instead of using the global wiring scheme.
Bolt dropping wire, please
Adds secure airlock electronics

Also, secured_wires can be set through the airlock constructor.
Fixes accidental copypasta
Makes it harder to accidentally undress yourself
Cleaner implementation of secure electronics
Merge branch 'vending-anchor' into small-changes
Removes awful double wall from maintenance

Removes the awful looking double wall from the maintenance tunnel
between medical and engineering.
Merge branch 'double-wall' into small-changes
Merge branch 'undress' into small-changes
Merge pull request #5096 from mwerezak/small-changes

A bunch of small changes