Added Matrox Mystique emulation. This is a work in progress, and has a few known

issues :
- Only YUV supported for scaled ILOAD operations
- Several BLTMOD formats missing
- Bad texturing in Actua Soccer
- Flickering in Croc (broken vsync waiting?)
- Turok doesn't swap buffers correctly
- Some missing features

src/ibm.h

@@ -302,6 +302,8 @@ enum
 	GFX_PGC,	/*Professional Graphics Controller */
 	GFX_IM1024,	/*Vermont Microsystems IM1024 */
 	GFX_EGAWONDER800, /*ATI EGA Wonder 800+*/
+	GFX_MYSTIQUE,   /*Matrox Mystique*/
+
         GFX_MAX
 };