Merge in changes from our upstream #457

Icon difference rendering

Please file any issues here.

Icons with diff:

MODIFIED - icons/mob/items/lefthand.dmi (0)

State Name (duplicate)	Old Icon	New Icon	Status
saw3 (0)			Deleted
saw (0)			Created
blahaj (0)			Created
hedget			Modified

MODIFIED - icons/obj/bones_vr.dmi (0)

State Name (duplicate)	Old Icon	New Icon	Status
generic (0)			Deleted
synth-1 (0)			Created
synth-2 (0)			Created
generic-2 (0)			Created
generic-3 (0)			Created
generic-1 (0)			Created
generic-4 (0)			Created
synth-4 (0)			Created
synth-3 (0)			Created

MODIFIED - icons/inventory/suit_store/mob.dmi (0)

State Name (duplicate)	Old Icon	New Icon	Status
jetpack-breaker-on (0)			Created
jetpack-breaker (0)			Created

DELETED - icons/obj/zippo.dmi (0)

State Name (duplicate)	Old Icon	New Icon	Status
blackzippo (0)			Deleted
blackzippoon (0)			Deleted
bluezippo (0)			Deleted
bluezippoon (0)			Deleted
zippo (0)			Deleted
zippoon (0)			Deleted
zippo1 (0)			Deleted
zippoclick (0)			Deleted
engravedzippo (0)			Deleted
engravedzippoon (0)			Deleted
damelighter (0)			Deleted
damelighteron (0)			Deleted
13lighter (0)			Deleted
13lighteron (0)			Deleted
snakelighter (0)			Deleted
snakelighteron (0)			Deleted
goldzippo (0)			Deleted
goldzippoon (0)			Deleted
moffzippo (0)			Deleted
moffzippoon (0)			Deleted
redzippo (0)			Deleted
redzippoon (0)			Deleted
cappiezippo (0)			Deleted
cappiezippoon (0)			Deleted
commiezippo (0)			Deleted
commiezippoon (0)			Deleted
rainbowzippo (0)			Deleted
rainbowzippoon (0)			Deleted
gonzozippo (0)			Deleted
gonzozippoon (0)			Deleted
royalzippo (0)			Deleted
royalzippoon (0)			Deleted
ironiczippo (0)			Deleted
ironiczippoon (0)			Deleted
zippofire1 (0)			Deleted
zippofire2 (0)			Deleted
zippofire3 (0)			Deleted