Added datum mutations

Also removed some mob vars like sdisabilities and merged the usability
with disabilities
Removed need for mutations var, they are now handled in dna
Removed blinded var, now its handled by eye_blind being bigger than zero
Ands lots, lots of other shit in files that used mutations

THIS IS NOT FINISHED, WORK IN PROGRESS, DONT JUMP ON IT
This runtimes.
```
proc name: on life (/datum/mutation/human/tourettes/on_life)
  source file: mutations.dm,272
  usr: null
  src: Tourettes Syndrome (/datum/mutation/human/tourettes)
  call stack:
Tourettes Syndrome (/datum/mutation/human/tourettes): on life(Izaiah Gettemy (/mob/living/carbon/human))
Izaiah Gettemy (/mob/living/carbon/human): Life()
/datum/controller/game_control... (/datum/controller/game_controller): process mobs()
/datum/controller/game_control... (/datum/controller/game_controller): process()
runtime error: list index out of bounds
```