Various fixes related to the C++11/14 update (see issue #3140)

- Convert scoped_ptr to std::unique_ptr from <memory>
- Convert arraysize to base::size from include/base/cef_cxx17_backports.h
- Convert NULL to nullptr
- Include include/base/cef_callback.h instead of include/base/cef_bind.h
- Implicit conversion of CefRefPtr<T> or scoped_refptr<T> to T* is gone;
  use .get() instead

See the issue for additional details.

libcef_dll/cpptoc/cpptoc_scoped.h

@@ -10,7 +10,6 @@
 #include "include/base/cef_macros.h"
 #include "include/capi/cef_base_capi.h"
 #include "include/cef_base.h"
-#include "libcef_dll/ptr_util.h"
 #include "libcef_dll/wrapper_types.h"
 
 // Wrap a C++ class with a C structure. This is used when the class