Assorted Sprite-Related Fixes

Candy canes no longer have transparent stripes
- Fixes #2876
- Moved candy.dmi into the icons/obj/food/ folder
- Removed the candy sprites from the food.dmi file

Replaced reagentchocolatebar with cocoa_pile
- This is what is made when you spill chocolate reagent on the floor,
and is not the same as the chocolate bars you use for making stuff
- Should avoid confusion and also fixes a potential infinite-generation
exploit of chocolate and sugar
- Fixes #2614

Flamethrower in-hand icons now display properly
- Fixes #2856
- Will always show a tank in the in-hand, regardless of if a tank is
attached

Smartfridges will now remain visible when you open their panels with a
screwdriver
- Fixes #2847

Hand-rolled cigarettes now show on sprite when equipped as a mask
- Fixes #2427

Apple seeds now have a proper seed packet
- Fixes #1409
- Will make the xenobotany machines mentioned in the issue buildable in
a separate PR, as that is beyond scope / feature-request

code/game/objects/items/weapons/flamethrower.dm

@@ -4,6 +4,8 @@
 	icon = 'icons/obj/flamethrower.dmi'
 	icon_state = "flamethrowerbase"
 	item_state = "flamethrower_0"
+	lefthand_file = 'icons/mob/inhands/guns_lefthand.dmi'
+	righthand_file = 'icons/mob/inhands/guns_righthand.dmi'
 	flags = CONDUCT
 	force = 3.0
 	throwforce = 10.0