Fix entering an intangible FOF causing minecart derailment explosions. (Probably; I didn't get the bug to happen in the first place, but this looks like a likely culprit.)

# Conflicts:
#	src/p_enemy.c

There's code in B_RespawnBot that handles gravflip, but none in B_CheckRespawn. This commit fixes that. (Only done on this branch since bots had already been touched.)

Add solidity back to MT_SALOONDOOR, to work as a backup in case MT_SALOONDOORCENTER doesn't work (which it has issues with in one location in ACZ2 for some reason, and I can't identify why).

Fully resolves #209, in any case.

* Tailsbots can't get into Minecarts.
* Tailsbots will stop trying to move around when the player gets pw_carry, which usually means some sort of big gimmick is happening and trying to move along with it would make the tailsbot look stupid.

* Make the center be the object stuff collides with, so that if the door is open people can't slip through.
* Add an MF_AMBUSH enhancement to allow non-minecart players to travel through.
* Make A_SaloonDoorSpawn more customisable. (var1 = object type, var2 = distance sides should be placed apart)

Addons menu cleanup

See merge request STJr/SRB2Internal!316

ACZ3 intro

Closes #217

See merge request STJr/SRB2Internal!346

Deep Sea Zone 3 hardcoding

Closes #185

See merge request STJr/SRB2Internal!349

Automap fixes

See merge request STJr/SRB2Internal!348

Patch fixes (Resolves #230)

Closes #230

See merge request STJr/SRB2Internal!347

Several bug fixes!

Closes #210, #192, and #189

See merge request STJr/SRB2Internal!345

Resolve "Tails AI should die when taking damage in Ultimate"

Closes #231

See merge request STJr/SRB2Internal!344

Trigonometric input capping

See merge request STJr/SRB2Internal!343

Controller hotplug support.

See merge request STJr/SRB2Internal!342

* https://cdn.discordapp.com/attachments/428262628893261828/626792815451701259/srb20006.gif
* Add fadeout instead of slapstick for Fang Clone Fighter death.
* Allow placed Fang and Metal Sonic objects to be marked as Clone Fighters always through presence of MTF_EXTRA.

Correctly restrict MF_NOCLIPTHING-objects from being interacted with from both moving and non-moving side.

Remember when Lach recorded their live reaction to 2.2 so far? Do you recall what the reaction to ACZ3 was?

If you don't, the reaction was "WHAT?? Why is he here? This is GREAT but, what??" And while the reaction is on the positive end of things, it's stll clearly not advisable for our defining Big Reveal of the already huge update.

To this end: Here is a mini cutscene! https://cdn.discordapp.com/attachments/428262628893261828/626207624043429898/srb20005.gif
* He's digging through Eggman's trash.
* Clearly doesn't expect to see you!
* Ready for a fight all the same.
* You can attack him during the mini cutscene if you're impatient.
* Skipped if you give him MTF_AMBUSH.
* Requires new assets (including map) to test, but I'm not ready to make a MR yet because I have other thoughts first.

Also, since I was poking around in p_enemy.c, I fixed A_Boss1Laser's issues (not working with direct 2.1 port states and having the weird secondary attack).