Add support for 512 palette, new deepmhasis method

- Increase palette table from 256 to 1024. the 1st 256 colors are used
  by FCEUmm internally and for compatibility (PS2/PSP will use the old
  emphasis located in this area). New 512 colors with emphasis will be
  read from offset 256 of this palette table.
- Support loading of 512 palette, this will still use the same nes.pal
  filename.

src/driver.h

@@ -136,7 +136,7 @@ void FCEUI_SetBaseDirectory(const char *dir);
 /* Tells FCE Ultra to copy the palette data pointed to by pal and use it.
    Data pointed to by pal needs to be 64*3 bytes in length.
 */
-void FCEUI_SetPaletteArray(uint8 *pal);
+void FCEUI_SetPaletteArray(uint8 *pal, int nEntries);
 
 /* Sets up sound code to render sound at the specified rate, in samples
    per second.  Only sample rates of 44100, 48000, and 96000 are currently