Merge branch 'master' of http://git.magicalgirl.moe/STJr/SRB2Internal.git into Deez_NewUserXperiences

Add a little header to the colour cube menu so you see the state of ALL of the colours, not just the three that fit on screen at once.

https://cdn.discordapp.com/attachments/293238104096112641/307998638246723597/srb20016.png

* Completely hides instead of greying stuff out.
* "Modifications" has been renamed to "Add-ons", since that's a more direct term.

Reset captions where appropriate (including in S_StopSounds(), as it should have been doing all along).

There are now captions for specific types of music! (Currently signified with an M, but I'll change that in a bit...) A whole lotta things needed to be modified for this, though.

* Serious refactor of - and internal exposure of - what has become S_StartCaption().
* Renaming of a few existing captions.
* The prevention of access to - or writing over - sfx_None's stuff in SOC or Lua.
* The new Lua wrapper function S_StartMusicCaption(string, tics, optional player), which essentially allows custom music captions to be created. (This is best used for stuff like final lap music in SRB2 Kart or bonus time in a thokker-like game, not a comprehensive Now Playing expy. That'd be a different kettle of fish.)

Also, updated all the lock-on stuff to use P_IsLocalPlayer instead of rolling my own.

* be more efficient
* fade away early if they stop playing
* make their current max stick-around time longer
* make the fade time/etc easier to modify

Made updating the captions a part of S_UpdateSound(), not SCR_ClosedCaptions() (which really should have been render-only all along).

A less memetic message: On permission of Mystic, rejiggered a few things such that Race uses cv_competitionboxes, allowing the menu to be nicer.

Also:
* disabled the doomednum for ? boxes
* made A_MixUp play sfx_lose if you're in a gametype that can't use it
* Removed the all-teleporters option from cv_competitionboxes. It could just be done by tweaking the random monitor toggles, anyways.

Per Inu's request, semi-broken (both game mechanically and engineering wise) directional information has been removed from the Captions. It's now "in-level" (dot) and "sourceless" (no dot) only.

Addfile directories fix

This is a fix for this bug: https://mb.srb2.org/showthread.php?t=42279

See merge request !166

Falling rocks fix

This fixes the rock spawners' rocks not being removed if they rolled down to the ground from a slope rather than bouncing (see https://mb.srb2.org/showthread.php?t=41963)

See merge request !162

https://gfycat.com/PlumpShowyBream https://gfycat.com/AlarmingLoathsomeBelugawhale

DrawFill made not stupid

made it more consistent with other drawing functions; doesn't draw off of the sides, and doesn't ignore snapping or widths for reasons that don't make sense
(for instance: the green bar in MI's test script showed *above* the blue one in non-green resolutions in 2.1.17)

See merge request !173

Merge branch 'master' of http://git.magicalgirl.moe/STJr/SRB2Internal.git into Deez_NewUserXperiences

Ended up being stressed and not getting any real work done, so figured I'd finish up the checklist system.

The start of an unlockable checklist revamp. Require more UC_ constant acknowledgement and the ability to scroll, but I can't work on this for a while so.

Also, replaced ridiculously ambiguous "impossible error" with more descriptive alternative.

Also, optimised gif headwrite's palette writing.