Just kidding, I just deleted NONET

Replays now store & validate the add-on list before loading them. Custom characters can now be allowed in Record Attack.

- Prevent connection timeout during the waiting gamestate from the last commit.
- Keep client connections alive during fades / other internal loops.
- More consistently timeout clients when they reach the end of BACKUPTICS.
- Dedicated servers will not run any game logic if no nodes are sending packets to it, to reduce CPU usage when there is no one interacting with your server.
  - Unlike SRB2Kart, the amount of time is configurable with the "dedicatedidletime" console variable. Setting this to 0 will disable this feature.
- CL_SendClientCmd uses exact packet types instead of magic number offsets.

All gamestates besides GS_LEVEL are unsupported by the save game functions. This commit forces players joining during these gamestates into GS_WAITINGPLAYERS, which is a basic gamestate that just maintains the connection until we can enter the start of a new one. Also provides an extremely simple drawer for GS_WAITINGPLAYERS so the joining player knows what's going on.

Currently, emblems share with everyone. Will add an option to toggle this.

These commands be run from Lua:

- add
- addfile
- addfolder
- archivetest
- ban
- banip
- causecfail
- cecho
- cechoduration
- cechoflags
- changeteam
- changeteam2
- charability
- charspeed
- cheats
- clearbans
- clearscores
- connect
- countmobjs
- csay
- demote
- devmode
- displayplayer
- downloads
- drop
- droprate
- dumplua
- echo
- exitgame
- exitlevel
- gametype
- getallemeralds
- getplayernum
- god
- gravflip
- help
- hurtme
- isgamemodified
- jumptoaxis
- kick
- listwad
- login
- manual
- map
- mapmd5
- masterserver_update
- memdump
- memfree
- mod_details
- motd
- noclip
- nodes
- notarget
- numnodes
- numthinkers
- objectplace
- password
- pause
- ping
- playintro
- promote
- quit
- reloadbans
- resendgamestate
- resetcamera
- resetemeralds
- restartaudio
- retry
- rteleport
- runsoc
- savecheckpoint
- say
- sayteam
- sayto
- scale
- screenshot
- serverchangeteam
- setcontinues
- setlives
- setrings
- showbanlist
- showmap
- showscores
- showtime
- skynum
- startmovie
- stopdemo
- stopmovie
- suicide
- teleport
- toggle
- togglemodified
- toggletwod
- tunes
- version
- vid_info
- vid_modelist
- vid_nummodes
- weather

These cvars can be modified by Lua.

- advancemap
- allowexitlevel
- allowjoin
- allowmlook
- allowseenames
- allowteamchange
- autobalance
- basenumlaps
- cam2_adjust
- cam2_centertoggle
- cam2_curdist
- cam2_curheight
- cam2_dist
- cam2_height
- cam2_lockaimassist
- cam2_lockedinput
- cam2_orbit
- cam2_rotate
- cam2_rotspeed
- cam2_shiftfacingchar
- cam2_simpledist
- cam2_simpleheight
- cam2_speed
- cam2_still
- cam2_turnfacingability
- cam2_turnfacingchar
- cam2_turnfacinginput
- cam2_turnfacingspindash
- cam2_turnmultiplier
- cam_adjust
- cam_centertoggle
- cam_curdist
- cam_curheight
- cam_dist
- cam_height
- cam_lockaimassist
- cam_lockedinput
- cam_orbit
- cam_rotate
- cam_rotspeed
- cam_shiftfacingchar
- cam_simpledist
- cam_simpleheight
- cam_speed
- cam_still
- cam_turnfacingability
- cam_turnfacingchar
- cam_turnfacinginput
- cam_turnfacingspindash
- cam_turnmultiplier
- color
- color2
- competitionboxes
- cooplives
- coopstarposts
- countdowntime
- exitmove
- flagtime
- forceskin
- friendlyfire
- gravity
- hidetime
- inttime
- itemfinder
- killingdead
- matchboxes
- maxplayers
- mute
- numlaps
- overtime
- pausepermission
- playersforexit
- pointlimit
- powerstones
- respawndelay
- respawnitem
- respawnitemtime
- restrictskinchange
- ringslinger
- runscripts
- scrambleonchange
- seenames
- servername
- showhud
- showinputjoy
- skin
- skin2
- specialrings
- startinglives
- tailspickup
- teamscramble
- timelimit
- touchtag
- tv_1up
- tv_bombshield
- tv_eggman
- tv_forceshield
- tv_invincibility
- tv_jumpshield
- tv_recycler
- tv_ringshield
- tv_superring
- tv_supersneaker
- tv_teleporter
- tv_watershield

This reverts commit 696e2ab9, reversing
changes made to d98d5949.

This reverts commit 96bfd8ce, reversing
changes made to 24f9ec4e.

This reverts merge request !1920

Just kidding, I just deleted NONET

renderhitbox
- Tangible - collision activating objects, minus rings
- All - every object
- Intangible - the opposite of Tangible, also no rings
- Rings - rings

Instead of modifying the game, cheats now set a separate "cheats were used in this session" variable, which returns some of the old behavior.

HOWEVER, cheats will STILL allow spawning / collecting emblems & unlocking unlockables. Cheats will purely prevent saving progress. (It was always frustrating that devmode would make debugging unlockable features harder...)

Lastly, the function to set no-saving was exposed to Lua (`G_SetUsedCheats(silent)`). Just thought it'd be useful for large-scale gamedata-using mods that want to add their own cheat commands.

Implements the SDL Game Controller API, haptics, and axis bindings.