Did not get to finish all refactoring or even compile this, I'll continue later

Preview is fairly basic, and only shows players
rewinding. Full state is restored via reloading
the replay and jumping to the timestamp once
the rewind is done.

This will probably nip a possible issue
with player cmds getting read/wrote inconsistently
if a player joins or leaves.

May not make it to R1, but oh well

Weather is already run client-side. What if we ran it render-side, for major performance gains? This commit will answer all your questions - and more!

According to wolfs, this improves fps. Let's confirm, shall we?

Nuke a bunch of iteration things that have no purpose in SRB2Kart. A full explanation of my reasoning and what it affects is as follows.

p_inter.c -
	Everything to do with setting states for starposts
		In SRB2Kart, starposts are invisble. We don't need to loop through all thinkers just to set their states when there's no visible effect of the state-setting. In addition, it has no consequences for gameplay - starposts have long been silent here, and all checking is done regarding their health, not their state.
	Remove extremely low-traffic conditionals (MT_FLINGEMERALD collision height extension, for example)
		These objects serve no functional purpose during regular SRB2Kart gameplay. Why should every other object have to pay an admittedly minor performance hit just for them?
	Disable all mechanisms of damaging bosses or enemies with the player's physical contact
		With the exception of Sapphire Coast, no MF_ENEMY objects exist in the entirety of the standard roster. In addition, the conditions for damaging the enemies were impossible to achieve, because they required vanilla SRB2 mechanics such as "jumping", "spindashing", or "super". Therefore, they can be safely commented out.
	Disable NiGHTS-related material (excepting bumper, hoop, and wing-emblem objects)
		NiGHTS is fundamentally incompatible with regular kart gameplay and I believe was already broken. Therefore, any mechanism which enters, aids, or abets it can be safely disabled.
	Comment out Tag mechanisms
		Tag is the only vanilla multiplayer gametype which has sufficient gameplay depth and complexity (HEYOOOOOOOOO) to require dedicated thinking in and of itself in order to manage. This thinking is irrelevant to Kart's functioning, and can be neutered easily.
d_clisrv.c
	Comment out Tag mechanisms
		See p_inter.c
d_netcmd.c
	Disable several devmode commands which are irrelevant to SRB2Kart gameplay
		When investigating for references to NiGHTS material, I discovered that these remained untouched. In order to present a more coherent game, I have hidden the ones that serve no purpose for us.
	Comment out Tag mechanisms
		See p_inter.c
g_game.c
	Disable NiGHTS-related material
		See p_inter.c
	Disable some team-related material
		Teams are not present in SRB2Kart at present. Obviously we'd want to reconsider for future, but it doesn't need to be run right now.
	Everything to do with setting states for starposts
		See p_inter.c
m_cheat.c
	Disable several devmode commands which are irrelevant to SRB2Kart gameplay
		See d_netcmd.c
p_map.c
	Remove extremely low-traffic conditionals (MT_EGGSHIELD collision, for example)
		See p_inter.c
	Disable NiGHTS-related material
		See p_inter.c
p_mobj.c
	Disable P_EmeraldManager
		Power stones, despite their relevance in vanilla Match, are not in SRB2Kart's Battle. No management of nonexistent emeralds is required.
p_setup.c
	Everything to do with setting states for starposts
		See p_inter.c
p_spec.c
	Disable NiGHTS-related material
		See p_inter.c
	Everything to do with setting states for starposts
		See p_inter.c
p_telept.c
	Everything to do with setting states for starposts
		See p_inter.c
p_tick.c
	Disable some team-related material
		See g_game.c
	Disable P_EmeraldManager
		See p_mobj.c
	Do not run shields
		Shield objects are not run under the vanilla system; the Thunder Shield is a domain-specific recreation using a standard mobjthinker.
	Do not run special stages
		SRB2Kart does not have special stages.
	Comment out Tag mechanisms
		See p_inter.c
y_inter.c
	Disable some team-related material
		See g_game.c
p_user.c
	Disable NiGHTS-related material
		See p_inter.c
	Disable 2d movement for players
		2D mode? In a kart racer? :nick:

Experimental: Making the ghetto waypoints we have right now their own mobj list in order to make them slightly less bullshit

* Encore on the voting screen! Appears randomly once unlocked in the same slot as that which sometimes represents a gametype change (odds inflated for testing purposes).
* A better representation of an Encore level, now with inverted graphics (a special remapping we can now use elsewhere whenever if we want!) and a floating Ruby!
* Decouple encore's setting from cv_kartencore on mapload. Instead, bake it into D_MapChange and related, which will only some of the time be fed by cv_kartencore's value.
* Encore mode now has a special mapheader palette setting, "encorepal", rather than using the same one as non-encore.

	* Activates when there are less than two non-spectators in a netgame.
	* Shows flashing text at the bottom of the screen.
	* Prevents drawing several UI elements that only make sense with multiple players.
	* Prevents matchesplayed being increased.
* Improve the mapreset timer's behaviour.
	* Now you get to see the HERE COMES A NEW CHALLENGER screen as the starting frame of the relevant map transition, since it happens on mapreset being 1 rather than 0.
	* Make a bunch of normal gameplay stuff that might've activated unnecessarily during mapreset now not able to.
	* Hide some other stuff that might've been visible for no good reason.
* Improve Mirror mode.
	* First person now works with it!
	* Tweaked the minimap player heads. Although the main section of the automap is mirrored, it feels... wrong to mirror the player head? IDK, you may wish to revert this, but given that everything else is the right way around except for the level itself...* Disable the titlescreen demos, at least until we actually gear up for release and make real ones.
* Disable the titlescreen demos, at least until we actually gear up for release and make real ones.

- Mines last twice as long
- Mines can appear in 1st with a measly 5% chance, for maximum ass-blasting
- Mine shiiiiink sound no longer plays globally
- Thrown Bananas and Eggman Monitors bounce off walls like Mines
- Hyudoro can steal from anyone
- Halved invincibility alarm/music distance
- Getting out Orbinaut/Jawz plays a shield sound
- Using Shrink plays a devastating Chaotix sound
- SPB plays a high-pitched wail when it's locked in
- Hyudoro plays a ghosty sound when used
- Fixed Battle arrow roulette

Shrink also plays its sound, and Shrink/Grow have slower scaling speeds

- 30 sec cooldown on all lightning types
- Delay before Blue Lightning hits, based off of distance
- Blue Lightning can swap targets if 1st place is passed
- Blue Lightning can only be handed out if 2nd is far away enough from first

An unlockables/time emblems update, the stats screen shows all maps without needing to visit each one, and respawning is enabled in Record Attack now