Fix game_mode and game_type enums

[Bumber64]

Fix game_mode and game_type enums by removing num value and setting NONE to -1.

[quietust]

This change was incorrect - as the enums are defined in Toady's headers, the NONE entries are NOT set to -1!

enum GameMode
{
	GAMEMODE_DWARF,
	GAMEMODE_ADVENTURE,
	GAMEMODENUM,
	GAMEMODE_NONE
};

enum GameType
{
	GAMETYPE_DWARF_MAIN,
	GAMETYPE_ADVENTURE_MAIN,
	GAMETYPE_VIEW_LEGENDS,
	GAMETYPE_DWARF_RECLAIM,
	GAMETYPE_DWARF_ARENA,
	GAMETYPE_ADVENTURE_ARENA,
	GAMETYPE_ADVENTURE_DUNGEON,
	GAMETYPE_DWARF_TUTORIAL,
	GAMETYPE_DWARF_UNRETIRE,
	GAMETYPE_ADVENTURE_WORLD_DEBUG,
	GAMETYPENUM,
	GAMETYPE_NONE
};