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/vsuni.c

@@ -292,8 +292,8 @@ void FCEU_VSUniCheck(uint64 md5partial, int *MapperNo, int *Mirroring) {
 
 	while (vs->name) {
 		if (md5partial == vs->md5partial) {
-			if (vs->ppu < RCP2C03B) pale = vs->ppu;
-			else pale = 5;
+			if (vs->ppu < RCP2C03B) default_palette_selected = vs->ppu;
+			else default_palette_selected = 5;
 			*MapperNo = vs->mapper;
 			*Mirroring = vs->mirroring;
 			GameInfo->type = GIT_VSUNI;