Massive refactoring of all code + audio skeleton.

This should make it easier to find files and (in the future) split things
up into separate libraries.
It also changes around emulator initialization to make it a little more
difficult to do things out of order and a little more sensible as to when
real init work happens.
Also adding a skeleton audio system/driver and reworking CPU register
access to be more extensible.

src/xenia/gpu/d3d11/d3d11_gpu.cc

@@ -0,0 +1,44 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2013 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include <xenia/gpu/d3d11/d3d11_gpu.h>
+
+#include <xenia/gpu/d3d11/d3d11_graphics_system.h>
+
+
+using namespace xe;
+using namespace xe::gpu;
+using namespace xe::gpu::d3d11;
+
+
+namespace {
+  void InitializeIfNeeded();
+  void CleanupOnShutdown();
+
+  void InitializeIfNeeded() {
+    static bool has_initialized = false;
+    if (has_initialized) {
+      return;
+    }
+    has_initialized = true;
+
+    //
+
+    atexit(CleanupOnShutdown);
+  }
+
+  void CleanupOnShutdown() {
+  }
+}
+
+
+GraphicsSystem* xe::gpu::d3d11::Create(Emulator* emulator) {
+  InitializeIfNeeded();
+  return new D3D11GraphicsSystem(emulator);
+}