Misc. code changes in preparation for Hyudoro final pass + debugcheese cvar

See merge request KartKrew/Kart!1503

Change Scroller Direction (linedef 435): Do not crash on Tag_Find for sidedef scrollers

See merge request KartKrew/Kart!1506

Hyudoro becomes very real

See merge request KartKrew/Kart!1504

- Player invisibility is preserved for other players
- Flicker blendmode (and visibility, for other players) at
  beginning and end of hyudorotimer

- Carry back item capsule, painted with the skincolor of
  the player who was stolen from
- Give player item by orbiting and shrinking into the
  player like an emerald
  - Lock player item box while animation plays, draw an
    empty item box on the HUD
  - At end of animation, burst item capsule to place item
    in player's hotbar
- Hyudoros can no longer stack items in the hotbar --
  consistent with item capsules
  - (If you have a Super Ring in your hotbar and Hyudoro
    is holding a Super Ring too, it will wait for you to
    use yours)

---

MT_ITEMCAPSULE changes:

- extravalue2 != 0: use this color on caps
- MF2_STRONGBOX: award items like the roulette
  - Super Ring is placed in the hotbar instead of awarding
    rings directly
  - SPB is placed in the hotbar instead of throwing it
    immediately
- DMG_INSTAKILL: don't respawn

- If player is in first place, they cannot use the stack
- Use ghost trick to lessen the effect, since modulate
  blendmode cannot be controlled with translucency

- Shadow flickers in high contrast colors while patrolling
- Shadow flickers black/white for short time after Hyudoro
  steals from a player
- (Resetting shadow for hovering stack already handled by
  append_hyudoro)

- Use P_SetTarget to handle reference counting properly
- Properly unlink from the start of the list

- Add Obj_SetEmeraldAwardee
  - Separate object receiving emerald from object being
    orbited
  - Obj_BeginEmeraldOrbit sets both, if the awardee isn't
    explicitly set
- Don't HUD track emeralds without emerald flag set

Tutorial Spray Cans

Closes #669

See merge request KartKrew/Kart!1498

R_GenerateTextureBrightmap: install bounds checking on patch columnofs

See merge request KartKrew/Kart!1478

Actual solution to Test Run dialogue in servers

Fix THAT ONE Garden Top bug, which is also a bug with Rocket Sneakers

Closes #610

See merge request KartKrew/Kart!1499

Fix UFO Catcher Emerald dying on death pits -- also a general fix to death pits

Closes #608

See merge request KartKrew/Kart!1497

Anti item farming

See merge request KartKrew/Kart!1492

Checkpoint Star Posts

See merge request KartKrew/Kart!1444