Doc updates

module_usb_audio/usb_buffer/testct_byref.xc

@@ -0,0 +1,15 @@
+#include <xs1.h>
+
+/* TODO Currently complier does not support inline select functions, hense this is in a seperate file to ensure this is not the case */
+#pragma select handler
+void testct_byrefnot(chanend c, unsigned &isCt) 
+{
+    if (testct(c)) 
+    {
+        isCt = 1;
+    }
+    else 
+    {
+        isCt = 0;
+    }
+}