AI now handles EMP-stun like other creatures do in their life.dm file

Previously AI would be stunned indefinitely after being hit with an EMP-blast. This would prevent emergency shutters from being operated.
The stun status is now adjusted down in the Life()-proc like is done in the base living.dm, which the AI living.dm does not ..() call.
Adds pandarsenic's approved custom cyborg

http://baystation12.net/forums/viewtopic.php?f=33&t=10641
Updates a item sprite and adds 2 approved items

http://baystation12.net/forums/viewtopic.php?f=33&t=10693
http://baystation12.net/forums/viewtopic.php?f=33&t=10678
Paths to new files are:
/obj/item/weapon/lighter/zippo/fluff/isaac_jachym
/obj/item/clothing/shoes/jackboots/fluff/kecer_eldraran
Merge pull request #5379 from PsiOmegaDelta/AIStun

AI now handles the sunned status like other creatures do in their life.dm file
Fixes the jackboots
Merge pull request #5384 from Jarcolr/custom_item

Updates a custom item sprite and adds 2 approved custom items
Merge pull request #5383 from Jarcolr/custom_synthethic

Adds Pandarsenic's approved custom cyborg sprites