Improvements to audout (#58)

* Some audout refactoring and improvements

* More audio improvements

* Change ReadAsciiString to use long for the Size, avoids some casting

Ryujinx.Audio/PlaybackState.cs

@@ -0,0 +1,8 @@
+namespace Ryujinx.Audio
+{
+    public enum PlaybackState
+    {
+        Playing = 0,
+        Stopped = 1
+    }
+}