- Separated the linedef activation types into a bit mask that allows combination

of all types on the same linedef. Also added a 'first side only' flag. This
  is not usable from Hexen or Doom format maps though but in preparation of
  the UDMF format discussed here:
  http://www.doomworld.com/vb/source-ports/43145-udmf-v0-99-specification-draft-aka-textmap/
- Changed linedef's alpha property from a byte to fixed point after seeing that
  255 wasn't handled to be fully opaque.
- fixed a GCC warning in fmodsound.cpp 

SVN r954 (trunk)

src/am_map.cpp

@@ -1353,8 +1353,9 @@ void AM_drawWalls (bool allmap)
 			{
 				if ((lines[i].special == Teleport ||
 					lines[i].special == Teleport_NoFog ||
+					lines[i].special == Teleport_ZombieChanger ||
 					lines[i].special == Teleport_Line) &&
-					GET_SPAC(lines[i].flags) != SPAC_MCROSS &&
+					(lines[i].activation & SPAC_PlayerActivate) &&
 					am_usecustomcolors)
 				{ // intra-level teleporters
 					AM_drawMline(&l, IntraTeleportColor);