Move DiscIO enums to a new file

At first there weren't many enums in Volume.h, but the number has been
growing, and I'm planning to add one more for regions. To not make
Volume.h too large, and to avoid needing to include Volume.h in code
that doesn't use volume objects, I'm moving the enums to a new file.
I'm also turning them into enum classes while I'm at it.

Source/Core/DiscIO/Enums.h

@@ -0,0 +1,62 @@
+// Copyright 2016 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "Common/CommonTypes.h"
+
+namespace DiscIO
+{
+// Increment CACHE_REVISION (ISOFile.cpp & GameFile.cpp) if these enums are modified
+
+enum class Platform
+{
+  GAMECUBE_DISC = 0,
+  WII_DISC,
+  WII_WAD,
+  ELF_DOL,
+  NUMBER_OF_PLATFORMS
+};
+
+enum class Country
+{
+  COUNTRY_EUROPE = 0,
+  COUNTRY_JAPAN,
+  COUNTRY_USA,
+  COUNTRY_AUSTRALIA,
+  COUNTRY_FRANCE,
+  COUNTRY_GERMANY,
+  COUNTRY_ITALY,
+  COUNTRY_KOREA,
+  COUNTRY_NETHERLANDS,
+  COUNTRY_RUSSIA,
+  COUNTRY_SPAIN,
+  COUNTRY_TAIWAN,
+  COUNTRY_WORLD,
+  COUNTRY_UNKNOWN,
+  NUMBER_OF_COUNTRIES
+};
+
+// Languages 0 - 9 match Nintendo's Wii language numbering.
+// Languages 1 - 6 match Nintendo's PAL GameCube languages 0 - 5.
+// NTSC GameCubes only support one language and thus don't number languages.
+enum class Language
+{
+  LANGUAGE_JAPANESE = 0,
+  LANGUAGE_ENGLISH = 1,
+  LANGUAGE_GERMAN = 2,
+  LANGUAGE_FRENCH = 3,
+  LANGUAGE_SPANISH = 4,
+  LANGUAGE_ITALIAN = 5,
+  LANGUAGE_DUTCH = 6,
+  LANGUAGE_SIMPLIFIED_CHINESE = 7,
+  LANGUAGE_TRADITIONAL_CHINESE = 8,
+  LANGUAGE_KOREAN = 9,
+  LANGUAGE_UNKNOWN
+};
+
+Country CountrySwitch(u8 country_code);
+u8 GetSysMenuRegion(u16 title_version);
+std::string GetCompanyFromID(const std::string& company_id);
+}