ACTUALLY fixes problems with borgs permanently breaking their syringes and being able to put modules into potted plants, which causes unwanted fuckery.
Reverts #7560
Adds a HUD for observers
Adds a HUD for rigs and mechs
Adds up/down buttons for AI hud
Add more tg style alerts
Fix some bugs with the tg alerts
Improve icon_states usage by caching it
Redo how respawning works, add a button to ghost hud for it
The default falloff value for sounds is 0.5 (lower means quieter).
There was only 3 things ingame with a sound falloff of a whole whopping 5 (10x)
These things were explosions, telepads, and instruments.
One had a volume of 25%, another one had a volume based on distance threshold, and you can probably guess which one of the bunch had a hardcoded 100% volume.
This adds throw_alert() and /obj/screen/alert, a system that allows you to do custom hud alerts for any variety of things from "You're too cold!" to mecha status indicators for the pilot.
There's quite a few things that actually got replaced; the
fire/oxy/tox/co2 alerts are all now just alerts, as is nutrition. There's also a number of new alerts, such as blindness, highness, legcuffed, buckled, handcuffed, and probably some more I missed; read code/_onclick/hud/alert.dm and see for yourself!
Additionally, a number of tweaks have been done to resisting code, to make it so that there's an indicator when you're buckled or handcuffed, and can just click the alert to start resisting. This includes a refactor that combines the logic for lockers, holders all into one proc, called container_resist().
Also, the health and internals indicator got moved down one tile each. Needed room for the alerts. If we add the oxygen tank action buttons from /tg/ and remove the internals indicator, the health indicator can go back where it was originally.
Alerts, pictured in the top right.

- 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.