Before: Every tick each HUD item would recalculate and redo images for every mob in view. For items like the secHUD where we're transversing implants and the various records this gets very expensive.
After: Mobs use their hud_list variable to store varius huditem images, when conditions change for those specific huditem images it updates the specific ones on demand. As a backup every 30 ticks or so the mob will update all of their hud_list.
Also: moved proc/RoundHealth() from 2 seperate locations into __HELPERS/mobs.dm
Conflicts:
code/modules/mob/living/living.dm
Infection chance now calculated differently for airborne and contact ones.
Contact viruses spread on: infected people touching others, people touching naked infected people (clothed parts do not spread it).
Airborne viruses spread on: breathing (20% chance, then chance depending on worn clothing), coughing (now 2 tiles instead of 1)
Both types spread from mucous and blood puddles because lazy.
Fixes:
Blood and mucus now spread viruses correctly.
Lowered output of hyperzine generation syndrome, since it caused dedly ODs.
-Fixed derp with analyser.
Refactoring virus2, Part II - Viruses.
-Removed obsolete curing/resistance methods.
-Split base.dm into disease2.dm, effect.dm, helpers.dm.
