Fixes crashes for newly-written demos that have files with absurdly long names attached

# Conflicts:
#	src/p_tick.c

Another spot that needs guarding

See merge request KartKrew/Kart-Public!320

Ensure skin index read from replay file is within numskins before drawing face

See merge request KartKrew/Kart-Public!319

Fixes desyncs with rotating polyobjs

If you're looking to this commit to figure out what a hypothetical 1.7 should change, also increment MODVERSION - in this commit's case it was already incremented by another branch.

Adjusts pview_old for relative teleport to attempt a contigious motion

Make all the join/leave sound effects have a `singularity` of `true` so that they don't stack super loud during major net interruption or multiple splitscreen player joins.

Instead of not running for server or admin, run for ALL players, but only avoid *kicking* local or admin players.
Fixes a bug where having a non-interacting splitscreen player could take down your server.

Repaired performance regression under certain play conditions

Allows vid_wait to work under software without having to switch to OpenGL and then back

Just a weird, meaningless footgun waiting in the wings for someone to catch themselves on. D_StartTitle works plenty fine here!

- ALWAYS kick someone who's about to stop the server because they're about to overrun TICQUEUE, even if they're in the joiner grace period
- Reduce the joiner grace period for normal ping limit to 10 seconds (from 30)
- Properly account for ignoring all local players when the host is splitscreen

Clear and draw all game hud hook calls to 1 list

See merge request KartKrew/Kart-Public!318

(cherry picked from commit 7e17eb85)

2cffc9b4 Clear and draw all game hud hook calls to 1 list

Clear and draw all game hud hook calls to 1 list

See merge request KartKrew/Kart-Public!318

Fixes splitscreen issues with lua hud hooks

Ensure view interpolates between T-1 to T

See merge request KartKrew/Kart-Public!317