`/icon` procs are not implemented

[wixoaGit]

Procs in the /icon object are missing implementations.

• [ ] Blend
  • [x] ICON_ADD (#964)
  • [x] ICON_SUBTRACT (#964)
  • [x] ICON_MULTIPLY (#1009)
  • [x] ICON_OVERLAY (#948)
  • [ ] ICON_AND
  • [ ] ICON_OR
  • [x] ICON_UNDERLAY (#948)
  • [x] Blending images (#948)
  • [x] Blending colors (#964)
• [ ] Crop
• [ ] DrawBox
• [ ] Flip
• [ ] GetPixel
• [x] Height
• [x] IconStates
• [x] Insert
• [ ] MapColors
• [x] Scale (#951)
• [ ] SetIntensity
• [ ] Shift
• [ ] SwapColor
• [ ] Turn
• [x] Width

[wixoaGit]

OpenSS13 makes use of Blend and DrawBox

[ike709]

I should also mention that you can't currently set a var to a new /icon()

[ike709]

Blend() partially done in https://github.com/OpenDreamProject/OpenDream/pull/948

[ike709]

Scale() completed in https://github.com/OpenDreamProject/OpenDream/pull/951

[itsmeow]

Scale() doesn't properly transform individual frames within the icon, instead just scaling the entire icon arbitrarily, without changing the images inside.