Intellivion copy paste enough stuff to get the sound working

Sound now fully implemented including in savestates

BizHawk.Emulation.Cores/Consoles/Intellivision/Intellivision.cs

@@ -52,6 +52,7 @@ namespace BizHawk.Emulation.Cores.Intellivision
 			_psg.Reset();
 			_psg.ReadMemory = ReadMemory;
 			_psg.WriteMemory = WriteMemory;
+			(ServiceProvider as BasicServiceProvider).Register<ISoundProvider>(_psg);
 
 			Connect();
 

BizHawk.Emulation.Cores/Consoles/Intellivision/PSG.cs

@@ -6,7 +6,7 @@ using BizHawk.Emulation.Common;
 namespace BizHawk.Emulation.Cores.Intellivision
 {
 	// Sound refactor todo: Implement ISoundProvider, and register _psg in the Intellivision core
-	public sealed class PSG
+	public sealed class PSG : ISoundProvider
 	{
 		public ushort[] Register = new ushort[16];
 
@@ -30,6 +30,37 @@ namespace BizHawk.Emulation.Cores.Intellivision
 			}
 		}
 
+		public void GetSamplesAsync(short[] samples)
+		{
+			throw new NotSupportedException("Async is not available");
+		}
+
+		public bool CanProvideAsync
+		{
+			get { return false; }
+		}
+
+		public SyncSoundMode SyncMode
+		{
+			get { return SyncSoundMode.Sync; }
+		}
+
+		public void SetSyncMode(SyncSoundMode mode)
+		{
+			if (mode != SyncSoundMode.Sync)
+			{
+				throw new InvalidOperationException("Only Sync mode is supported.");
+			}
+		}
+
+		public void GetSamplesSync(out short[] samples, out int nsamp)
+		{
+			short[] ret = new short[735 * 2];
+			GetSamples(ret);
+			samples = ret;
+			nsamp = 735;
+		}
+
 		public void GetSamples(short[] samples)
 		{
 			for (int i = 0; i < samples.Length / 2; i++)