Adds TGS4 from https://github.com/tgstation/tgstation-server to Virgo, allowing auto-update functionality and testmerges.
How well it runs depends on how @Arokha sets things up. :p
- Add additional can_atmos_pass value ATMOS_PASS_PROC which indicates custom behavior requiring calling the CanZASPass proc.
- The benefit being for the other three values we DON'T need to call CanZASPass at all! We already know the behavior without the overhead of a proc call.
- Obviously any atom with can_atmos_pass = ATMOS_PASS_PROC cannot now call ..() in CanZASPass() since the default behavior would be to (recursively) call CanZASPass()
- This required re-numbering the constants, so I also fixed all code that assumed particular values for the constants.
- Switched all types which overrode CanZASPass with custom logic to be can_atmos_pass = ATMOS_PASS_PROC
- Changed /turf/c_airblock() to skip calling /atom/movable/c_airblock() for the three can_atmos_pass values that don't require calling the proc.
- Instead of using auto_use_power to re-tally up machinery's power usage every cycle, track the steady "static" load separately from the transient "oneoff" usage. Machines then only need to inform the area when they use oneoff power or *change* their steady usage.
- Remove auto_use_power and stop SSmachines from calling it.
- Add vars to track "static" usage for each of the three power channels to /area
- Rename the existing three vars to "oneoff" so its clear what they mean (and to catch people accidentally updating them directly)
- Update area power procs and APCs to use the new variables.
- Rename /area/proc/use_power() to use_power_oneoff() to make it clear what it is doing.
- Deprecate /obj/machinery/use_power() in favor of use_power_oneoff() but don't delete yet. Can transition gradually.
- Add logic to the update_power procs on machines to calculate the deltas and update static area power whenever their usage changes.
- Add logic to machines to update area power when they are created, destroyed, or move.
- Moved /obj/machinery procs related to area power usage into machinery_power.dm to make them easier to find.
- Added or updated comments in several places to explain what is going on and how to use it.
