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
Note: polyobj_t's "translucency" is apparently a SIGNED integer, so in theory it's possible to get polyobj flats to use the "spanfunc = splatfunc" line using negative values. If this is not meant to happen, this should probably be fixed asap
Conflicts:
src/f_wipe.c
more detailed description: vissprites now store dispoffset in a separate variable from (y)scale, and uses it to influence order between sprites without it affecting the actual drawing of the sprites themselves
Compiling errors fixed in this commit:
* Various cases of mixed declaration and statement code
* Implicit declaration of slope functions (read: you forgot to put "include "p_slopes.h" in MORE than a few places)
* an odd case of a bad fixed_t to float typecase, cause by using P_GetZAt directly inside FIXED_TO_FLOAT
* a few minor cases of bad unsigned-signed comparisons
* no prototypes for some of the new slope functions. For goodness sake Red, this is basic stuff!
