Does not forbid seeing modded servers even if you haven't unlocked add-ons yet

Repairs the pre-CMake functionality of TESTERS builds having the format `ringracers_branch-name_TESTERS.exe`

Now you can host for testers using a bog-standard DEVELOP build.

It's easy enough for the host to verify any given player, and this is in fact the only HOSTTESTERS-specific sync change..!?

Fixes compiling TESTERS builds

ACS music functions: add optional bool to only affect player activator

See merge request KartKrew/Kart!1531

Stereo Mode: Add "Shf" (Shuffle) option

See merge request KartKrew/Kart!1517

Respawn things at Z position offset by linedef 80

Closes #542

See merge request KartKrew/Kart!1528

Some quake improvements

See merge request KartKrew/Kart!1523

Damage Polish

See merge request KartKrew/Kart!1524

Hanicef allocator changes, simplified memcpy and fixed alignment

See merge request KartKrew/Kart!1530

Move HOM removal from R_RenderPlayerView to D_Display

See merge request KartKrew/Kart!1532

This lets duplicate displayplayers[0] render correctly,
since repeating occurrences of displayplayers[0] won't
clear the screen multiple times.

Always clamp texturecolumn in sprite draw

See merge request KartKrew/Kart!1527

The libc memcpy is faster

K_CalculateTrackComplexity: format using fmt::format, to account for differences in size_t platform type

P_RespawnSpecials just calls P_SpawnMapThing again, so
this works.

Consolidate sound/music volume functions; kill HW3SOUND off the face of the game code

See merge request KartKrew/Kart!1518

This basically came to me in a dream, who am I to look the horse in its mouth

- Press to start a shuffled sequence, losing your current position in the autosequence.
    - Press again to disable, but keep your current track.
- Adjust horizontal offset of Stereo buttons slightly.
- More judiciously comment Sound Test functionality, to assist future maintainers.

Fix k_waypoint.cpp compile errors on clang

See merge request KartKrew/Kart!1525

Small ACS additions

See merge request KartKrew/Kart!1502

More circular by using pitch, takes gravity into account, actually has a code path for ring loss that's more than 5 rings

Intermission button prompt: Fix slide-out for non-roundqueue contexts

See merge request KartKrew/Kart!1516

Screen shake was being done from the Broly vfx, which does scaling shenanigans so it caused Proximity Mine explosions to make the camera go apeshit.

I'm also pretty sure the hitlag calcs Proximity Mine did for the broly effect was wrong, not sure though? I'm trying something else and I think it's better.

- Use easing functions for quake intensity
- Camera distance takes Z height into account

Track-based bot difficulty

See merge request KartKrew/Kart!1482