Cleaning up xdbf stuff.

- moving next to xex utils
- fixing error cases around icon setting (and allowing reset)
- making C++11
- abstracting a bit so future additions will be easier
- fixing non-xex uses

src/xenia/ui/window_win.h

@@ -31,7 +31,8 @@ class Win32Window : public Window {
   HWND hwnd() const { return hwnd_; }
 
   bool set_title(const std::wstring& title) override;
-  bool SetIconFromBuffer(void* buffer, size_t size) override;
+
+  bool SetIcon(const void* buffer, size_t size) override;
 
   bool is_fullscreen() const override;
   void ToggleFullscreen(bool fullscreen) override;