Add CubebUtils namespace and hook up cubeb logging

Source/Core/AudioCommon/CubebUtils.h

@@ -0,0 +1,14 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+
+struct cubeb;
+
+namespace CubebUtils
+{
+std::shared_ptr<cubeb> GetContext();
+}  // namespace CubebUtils