Fix R_AddSingleSpriteDef's I_Error messages
Whoops, seems I forgot about this little branch. Basically this fixes how for a character's sprites, a full sprite lump name is displayed instead of just its sprite prefix in the "R_AddSingleSpriteDef: No patches found for [sprite prefix] frame [frame character]" message (unlike when it occurs for non-character sprites), resulting in something like "R_AddSingleSpriteDef: No patches found for PLAYC2C8 frame \^" which does NOT help custom character authors at all as it just confuses them instead. (for the record, the problem would actually with the ^ frame and not the ones displayed after "PLAY")
Oh, and the same problem is also fixed for this similar message: "R_AddSingleSpriteDef: Sprite [sprite prefix] frame [frame character] is missing rotations"
See merge request !95
Spr2 freeslots
Needed for Miles, generally a good idea to have around anyway. Considering Miles uses it without problems, seems to work fine.
See merge request !24
* When moving slowly, P_InstaThrust at S_SKIN's maxdash forward, and set momz to S_SKIN's mindash upwards. Plays a tok noise (not thok). Hurts enemies/bosses, busts spikes/monitors/all types of bustable blocks.
* When moving quickly... doesn't do anything yet, but WILL do a slide.
Also, P_DoSpinDash is now renamed to P_DoSpinAbility, and CA_TWINSPIN users can bust all bustable blocks on collision too.
Setup:
* S_SKIN needs an "availability" line. Set to 0 to have always available, otherwise is assumed to be UINT8 unlockable number. If it's a valid unlockable, its name will be copied over with the character's realname.
* Define an unlockable via SOC or hardcode. If you don't want it visible on the Secrets menu, just set its type to None. Everything else is as normal - you can set the conditionset to whatever, objective, height, nochecklist, nocecho...
* radius - sets the player's radius for that skin.
* height - sets the player's normal height for that skin.
* spinheight - sets the player's spinheight for that skin.
* shieldscale - see http://i.imgur.com/BQ5DhKC.png for justification
R_SkinUnlock defines the circumstances under which a skin is available. For simplicty's sake, I've currently bound it to an S_SKIN variable so I can toggle it easily, but it WILL be replaced with a hook into the savegame system at some point.
* Currently has three tiers of unlock - freebie (forceskin or modeattacking via a loaded replay), Ringslinger Only, and SP/Coop and Ringslinger.
* I don't know anything about netcode so I basically decided to make R_SkinUnlock relevant only under local circumstances, try as hard as possible to stop bad skin info from getting sent to the server, and then admit defeat once the server has the information. If this is a bad choice, please discipline me and show me how to fix it.
* Character Select now checks for whether the character is hidden or not on menu load and does/undoes it based on that info, but will never touch one disabled via SOC. I also used this opportunity to optimise, checking for/filling out charsel pictures instead of doing it later. (It now also includes special casing for a select screen with zero characters!)
* Mode Attack now hides hidden characters in its character select based on SP rules.
Things that still need to be done:
* ForceSkin_OnChange. Is there a graceful way to handle this?
* No obvious skin name conflicts. Add a salt to the names of hidden skins, and then remove it when they're unhidden?
* The gap between Knuckles' skin number and the first custom character anybody adds will be way too obvious. A seperate hidden skin numbering system? Start at 32 and count up from there? There's a few ways...
* NAMEcL refers to a frame which is seen for the entirety of an object's left side.
* NAMEcR refers to a name which is seen for the entirety of an object's right side.
* NAMEcLcR does both sides.
* Having just a NAMEcL requires you to fill in the opposite side either with NAMEcn where n is 1 and 5 to 8 OR fill in with a NAMEcR
* Switches down the centerline of the object instead of at the ANGLE_202h interval for normal sprites.
* Characters were selected for 1) ease of use and 2) not getting in the way of adding support for zdoom's totally bananas 16-way sprite system at a later date if we so choose
