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.h

@@ -53,7 +53,8 @@ class Window {
     return true;
   }
 
-  virtual bool SetIconFromBuffer(void* buffer, size_t size) = 0;
+  virtual bool SetIcon(const void* buffer, size_t size) = 0;
+  void ResetIcon() { SetIcon(nullptr, 0); }
 
   virtual bool is_fullscreen() const { return false; }
   virtual void ToggleFullscreen(bool fullscreen) {}