Hopefully nothing requires drift reset from here.

The scary 22 merge

Closes #19, #80, #69, #94, #61, #64, #6, #27, #46, #47, #45, #43, #37, and #72

See merge request KartKrew/Kart!321

The old condition for player movement was...

1. player hasn't finished
2. player not in pain, or player in pain but on the ground

The else condition to this is therefore player has finished or player in pain
and in the air.

I believe K_MomentumToFacing (prior to bots) was only for letting the player
turn around after crossing the finish line, to face the camera.

(K_MomentumToFacing also does nothing in the air.)

Loading bar for startup

See merge request KartKrew/Kart!322

Adds a simple white loading bar at the bottom of startup, instead of covering the cool reference with text

Mockup of what it looks like, since the window's invisble when you try to print-scr it: https://cdn.discordapp.com/attachments/275750804227489794/769931098636943391/unknown.png

My wrist burns...

Turn the lua sector lines hack into a macro

See merge request STJr/SRB2!1187

Set cvars directly from Lua

See merge request STJr/SRB2!1205

Add multithreading option for CMake

See merge request STJr/SRB2!1204

Only invoke the Lua API for mobj hooks that need it

See merge request STJr/SRB2!1209

Do not let previous wait commands affect COM_BufInsertText

See merge request STJr/SRB2!1207

Fix G_GhostTicker crashing trying to read netvars as ghost data

See merge request STJr/SRB2!1203

NPO2 span function optimization

See merge request STJr/SRB2!1201

Kick clients that fail to catch up with server gamelogic

See merge request STJr/SRB2!1208