Simply put, `W_CheckNumForFolderStartPK3` and its `End` equivalent will never return INT16_MAX for nonexistence, and I don't want to break any assumptions elsewhere by modifying those functions directly, so this is the simplest possible fix.
* Fix off-by-one error I caused in the skin randomisation selection.
* Clean up signcolour set to never go outside of valid entry range.
* Fix the preventing-console-spam mechanism for invalid sprites viewed in-game by only setting the state's sprite/frame to S_UNKNOWN's if the object's sprite/frame is currenly equal to the state's.
* Store the number of frames per sprite2 run in the spr2frames struct.
* Reintroduce P_GetModelSprite2, to allow for the sprite2 defaulting system to be used to full advantage even in GL.
* Instead of splitting the SUPER and normal SPR2 stuff within the same cell of the struct, have them exist in different cells just like in the "normal" sprite2 structs.
* Allow for just providing spr2 frames in order without specifying which "normal" sprite2 frame it's supposed to replace.
Also:
* Fix FF_VERTICALFLIP-ignoring regression.
* Fix whitespace adjustment in win_dll.c
* Remove bracket in P_GetSkinSprite2 because I realised it was extraneous while making sure P_GetModelSprite2 worked with it.
* Make the skin to record with Metal rather than Flesh Sonic. (Allowed even if not unlocked!)
* Make the object that plays back the recording actually use the Metal skin, rather than just a seperate spriteset. (The boss will still need the spriteset, though.)
* Actively record the player's sprite2, frame, and followmobj, just like regular ghosts do.
* Disable dashmode while recording, for a fairer race.
* Fix a probably long-standing bug where, while recording, being "hurt" would get Metal stuck in pain frames until they physically left the area of hurt.
* Always start Metal recording in wait frames for bonus taunting.
Other relevant changes:
* Increment DEMOVERSION *again*.
* Improve the Record Attack ghost followmobj recording to accomodate Metal's jet.
* Increase the datatype width of spritenum_t read/write for Record Attack ghosts because SUGOI 4: Back With A Revengance will probably also use more than 255 sprites alone.
* Return to standing frames (or prolong them if you're in them, rather than going to wait frames) if the player rotates on the spot with enough force.
* This was specifically done *for* Metal recording, but I decided it looked good enough to enable all the time.
