quicknes: support the other included mappers (some aren't enabled by default for whatever reason)

BizHawk.Emulation.Cores/Consoles/Nintendo/QuickNES/LibQuickNES.cs

@@ -10,6 +10,11 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.QuickNES
 	{
 		public const string dllname = "libquicknes.dll";
 
+		/// <summary>
+		/// setup extra mappers.  should be done before anything else
+		/// </summary>
+		[DllImport(dllname, CallingConvention = CallingConvention.Cdecl)]
+		public static extern void qn_setup_mappers();
 		/// <summary>
 		/// create a new quicknes context
 		/// </summary>

BizHawk.Emulation.Cores/Consoles/Nintendo/QuickNES/QuickNES.cs

@@ -9,6 +9,11 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.QuickNES
 {
 	public class QuickNES : IEmulator, IVideoProvider, ISyncSoundProvider
 	{
+		static QuickNES()
+		{
+			LibQuickNES.qn_setup_mappers();
+		}
+
 		public QuickNES(CoreComm nextComm, byte[] Rom)
 		{
 			CoreComm = nextComm;

quicknes/bizinterface.cpp

@@ -19,6 +19,11 @@ public:
 
 #define EXPORT extern "C" __declspec(dllexport)
 
+EXPORT void qn_setup_mappers()
+{
+	register_optional_mappers();
+}
+
 EXPORT Nes_Emu *qn_new()
 {
 	return new Nes_Emu();